Moved to one SubgraphManifest schema file per protocol

This will make it easier to add new network and will improve error messages when someone will be using fields that do not exist on a specific network but does in other (`temlates` for example used in NEAR were given a bunch of errors like the support was possible while it should have displayed an error on the `templates` node itself).

Using `templates` on NEAR before this PR:

```
✔ Apply migrations
✖ Failed to load subgraph from ../graph-node-dev/subgraphs/near/data-source/testnet.yaml: Error in ../graph-node-dev/subgraphs/near/data-source/testnet.yaml:

  Path: templates > 0 > source
  No value provided

  Path: templates > 0 > mapping
  Unexpected key in map: receiptHandlers

  Path: templates > 0 > mapping > abis
  No value provided
```

And with this PR:

```
$ ./bin/graph build ../graph-node-dev/subgraphs/near/data-source/testnet.yaml
✖ Failed to load subgraph from ../graph-node-dev/subgraphs/near/data-source/testnet.yaml: Error in ../graph-node-dev/subgraphs/near/data-source/testnet.yaml:

  Path: /
  Unexpected key in map: templates
```

Author: maoueh

manifest-schema.graphql

@@ -0,0 +1,86 @@
+scalar String
+scalar File
+scalar BigInt
+
+type SubgraphManifest {
+  specVersion: String!
+  features: [String!]
+  schema: Schema!
+  description: String
+  repository: String
+  graft: Graft
+  dataSources: [DataSource!]!
+  templates: [DataSourceTemplate!]
+}
+
+type Schema {
+  file: File!
+}
+
+type DataSource {
+  kind: String!
+  name: String!
+  network: String
+  source: ContractSource!
+  mapping: ContractMapping!
+}
+
+type ContractSource {
+  address: String
+  abi: String!
+  startBlock: BigInt
+}
+
+type ContractMapping {
+  kind: String
+  apiVersion: String!
+  language: String!
+  file: File!
+  entities: [String!]!
+  abis: [ContractAbi!]!
+  blockHandlers: [BlockHandler!]
+  callHandlers: [CallHandler!]
+  eventHandlers: [ContractEventHandler!]
+}
+
+type ContractAbi {
+  name: String!
+  file: File!
+}
+
+type BlockHandler {
+  handler: String!
+  filter: BlockFilter
+}
+
+type BlockFilter {
+  kind: String!
+}
+
+type CallHandler {
+  function: String!
+  handler: String!
+}
+
+type ContractEventHandler {
+  event: String!
+  topic0: String
+  handler: String!
+}
+
+type Graft {
+  base: String!
+  block: BigInt!
+}
+
+type DataSourceTemplate {
+  kind: String!
+  name: String!
+  network: String
+  source: ContractSourceTemplate!
+  mapping: ContractMapping!
+}
+
+type ContractSourceTemplate {
+  abi: String!
+}

schemas/ethereum.graphql

@@ -0,0 +1,51 @@
+scalar String
+scalar File
+scalar BigInt
+
+type SubgraphManifest {
+  specVersion: String!
+  schema: Schema!
+  description: String
+  repository: String
+  graft: Graft
+  dataSources: [DataSource!]!
+}
+
+type Schema {
+  file: File!
+}
+
+type DataSource {
+  kind: String!
+  name: String!
+  network: String
+  source: ContractSource!
+  mapping: ContractMapping!
+}
+
+type ContractSource {
+  account: String
+  startBlock: BigInt
+}
+
+type ContractMapping {
+  apiVersion: String!
+  language: String!
+  file: File!
+  entities: [String!]!
+  blockHandlers: [BlockHandler!]
+  receiptHandlers: [ReceiptHandler!]
+}
+
+type BlockHandler {
+  handler: String!
+}
+
+type ReceiptHandler {
+  handler: String!
+}
+
+type Graft {
+  base: String!
+  block: BigInt!
+}

schemas/near.graphql

@@ -1,6 +1,7 @@
 const immutable = require('immutable')
 const EthereumTypeGenerator = require('./ethereum/type-generator')
 const EthereumTemplateCodeGen = require('./ethereum/codegen/template')
+const NearTemplateCodeGen = require('./near/codegen/template')
 const EthereumABI = require('./ethereum/abi')
 const EthereumSubgraph = require('./ethereum/subgraph')
 const NearSubgraph = require('./near/subgraph')
@@ -60,10 +61,7 @@ module.exports = class Protocol {
         'aurora',
         'aurora-testnet',
       ],
-      near: [
-        'near-mainnet',
-        'near-testnet'
-      ],
+      near: ['near-mainnet', 'near-testnet'],
     })
   }
 
@@ -108,6 +106,15 @@ module.exports = class Protocol {
     }
   }
 
+  hasTemplates() {
+    switch (this.name) {
+      case 'ethereum':
+        return true
+      case 'near':
+        return false
+    }
+  }
+
   getTypeGenerator(options) {
     switch (this.name) {
       case 'ethereum':
@@ -118,13 +125,17 @@ module.exports = class Protocol {
   }
 
   getTemplateCodeGen(template) {
+    if (!this.hasTemplates()) {
+      throw new Error(
+        `Template data sources with kind '${this.name}' are not supported yet`,
+      )
+    }
+
     switch (this.name) {
       case 'ethereum':
         return new EthereumTemplateCodeGen(template)
       default:
-        throw new Error(
-          `Template data sources with kind '${this.name}' are not supported yet`,
-        )
+        throw new Error(`Template data sources with kind '${this.name}' is unknown`)
     }
   }
 

src/protocols/index.js

@@ -27,7 +27,7 @@ const buildCombinedWarning = (filename, warnings) =>
     ? warnings.reduce(
         (msg, w) =>
           `${msg}
-  
+
     Path: ${w.get('path').size === 0 ? '/' : w.get('path').join(' > ')}
     ${w
       .get('message')
@@ -39,9 +39,21 @@ const buildCombinedWarning = (filename, warnings) =>
 
 module.exports = class Subgraph {
   static async validate(data, protocol, { resolveFile }) {
+    if (protocol.name == null) {
+      return immutable.fromJS([
+        {
+          path: [],
+          message: `Unable to determine for which protocol manifest file is built for. Ensure you have at least one 'dataSources' and/or 'templates' elements defined in your subgraph.`,
+        },
+      ])
+    }
+
     // Parse the default subgraph schema
     let schema = graphql.parse(
-      await fs.readFile(path.join(__dirname, '..', 'manifest-schema.graphql'), 'utf-8'),
+      await fs.readFile(
+        path.join(__dirname, '..', 'schemas', `${protocol.name}.graphql`),
+        'utf-8',
+      ),
     )
 
     // Obtain the root `SubgraphManifest` type from the schema
@@ -146,10 +158,7 @@ At least one such handler must be defined.`,
   }
 
   static validateContractValues(manifest, protocol) {
-    return validation.validateContractValues(
-      manifest,
-      protocol,
-    )
+    return validation.validateContractValues(manifest, protocol)
   }
 
   // Validate that data source names are unique, so they don't overwrite each other.
@@ -200,17 +209,13 @@ More than one template named '${name}', template names must be unique.`,
     return yaml.stringify(manifest.toJS())
   }
 
-  static async load(
-    filename,
-    { protocol, skipValidation } = { skipValidation: false }
-  ) {
+  static async load(filename, { protocol, skipValidation } = { skipValidation: false }) {
     // Load and validate the manifest
     let data = null
 
-    if(filename.match(/.js$/)) {
+    if (filename.match(/.js$/)) {
       data = require(path.resolve(filename))
-    }
-    else {
+    } else {
       data = yaml.parse(await fs.readFile(filename, 'utf-8'))
     }