fix documentation - Readme and gRPC docs (#364)

* add missing grpc doc
* remove unused features and links

Author: Vipul Rawat

README.md

@@ -28,10 +28,11 @@ We will focus ourselves towards deployment in kubernetes and aspire to provide o
 
 1. Simple API syntax
 2. REST Standards by default
-3. [Configuration management](https://gofr.dev/docs/v1/references/configs)
+3. Configuration management
 4. Inbuilt Middlewares
-5. [Error Management](https://gofr.dev/docs/v1/references/errors)
-6. [gRPC support](https://gofr.dev/docs/v1/advanced-guide/grpc)
+5. [gRPC support](https://gofr.dev/docs/advanced-guide/grpc)
+6. [HTTP service](https://gofr.dev/docs/advanced-guide/http-communication) with support for [Circuit Breaker](https://gofr.dev/docs/advanced-guide/circuit-breaker) and 
+[Health Check](https://gofr.dev/docs/advanced-guide/monitoring-service-health)
 
 ## 👍 Contribute
 If you want to say thank you and/or support the active development of GoFr:

docs/advanced-guide/grpc/page.md

@@ -0,0 +1,123 @@
+# gRPC
+We have already seen how GoFr can help ease the development of HTTP servers, but there are
+cases where performance is primiraliy required sacrificing flexibility. In these types of 
+scenarios gRPC protocol comes into picture. gRPC is an open-source RPC(Remote Procedure Call)
+framework initially developed by Google. [Learn more](https://grpc.io/docs/what-is-grpc/introduction/)
+
+## Prerequisites
+- Install the `protoc` protocol buffer compilation
+    - Linux, using `apt` or `apt-get`
+        ```shell
+        $ apt install -y protobuf-compiler
+        $ protoc --version  # Ensure compiler version is 3+
+        ```
+    - MacOS, using homebrew
+        ```shell
+        $ brew install protobuf
+        $ protoc --version  # Ensure compiler version is 3+  
+        ```
+- Install **Go Puligins** for protocol compiler:
+    1. Install prtocol compiler plugins for Go
+       ```shell
+       $ go install google.golang.org/protobuf/cmd/[email protected]
+       $ go install google.golang.org/grpc/cmd/[email protected]
+       ```
+    2. Update `PATH` for `protoc` compiler to find the plugins:
+       ```shell
+       $ export PATH="$PATH:$(go env GOPATH)/bin"
+       ```
+       
+## Creating protocol buffers
+For a detailed guide, please take a look at the [Tutorial](https://grpc.io/docs/languages/go/basics/) at official gRPC docs.
+
+Fistly, we need to create a `customer.proto` file to define our service and the rpc methods that the service provides.
+```protobuf
+// Indicates the protocol buffer version that is being used
+syntax = "proto3";
+// Indicates the go package where the generated file will be produced
+option go_package = "";
+
+service CustomerService {
+  // ...
+}
+```
+Inside the service one can define all the `rpc` methods, specifying the request and responses types.
+```protobuf
+service CustomerService {
+  // GetCustomer is a rpc method to get customer data using specific filters
+  rpc GetCustomer(CustomerFilter) returns(CustomerData) {}
+}
+```
+The `CustomerFilter` and `CustomerData` are two types of messages that will be exchanged between server
+and client. Users must define those for protocol buffer to serialize them when making a remote procedure call.
+```protobuf
+syntax = "proto3";
+
+message CustomerFilter {
+  int64 id = 1;
+  string name = 2;
+  // other fields that can be passed
+}
+
+message CustomerData {
+  int64 id = 1;
+  string name = 2;
+  string address = 3;
+  // other customer releated fields
+}
+```
+
+Now run the following command to gegnerate go code using the Go gRPC plugins:
+```shell
+protoc \
+--go_out=. \
+--go_opt=paths=source_relative \
+--go-grpc_out=. \
+--go-grpc_opt=paths=source_relative \ 
+customer.proto
+```
+Above command will generate two files `customer.pb.go` and `customer_grpc.pb.go` and these contain necessary code to perform rpc calls.
+In `customer.pb.go` you can find `CustomerService` interface-
+```go
+// CustomerServiceServer is the server API for CustomerService service.
+type CustomerServiceServer interface {
+    GetCustomer(context.Context, *CustomerFilter) (*CustomerData, error)
+}
+```
+User needs to implement this interface to serve the content to the client calling the method.
+```go
+package customer
+
+import (
+    "context"
+)
+
+type Handler struct {
+    // required fields to get the customer data
+}
+
+func (h *Handler) GetCustomer(ctx context.Context, filter *CustomerFilter) (*CustomerData, error) {
+	// get the customer data and handler error
+	return data, nil
+}
+```
+
+Lastly to register the gRPC service to the gofr server, user can call the `RegisterCustomerServiceServer` in `customer_grpc.pb.go`
+to register the service giving gofr app and the Handler struct.
+```go
+package main
+
+import (
+	"gofr.dev/pkg/gofr"
+	"gofr.dev/examples/grpc-server/customer"
+)
+
+func main() {
+	app := gofr.New()
+
+	customer.RegisterCustomerServiceServer(app, customer.Handler{})
+
+	app.Run()
+}
+```
+>Note: By default, grpc server will run on port 9000, to customize the port users can set GRPC_PORT config in the .env

docs/navigation.js

@@ -19,9 +19,9 @@ export const navigation = [
             { title: 'Circuit Breaker Support', href: '/docs/advanced-guide/circuit-breaker' },
             { title: 'Monitoring Service Health', href: '/docs/advanced-guide/monitoring-service-health' },
             { title: 'Handling Data Migrations', href: '/docs/advanced-guide/handling-data-migrations' },
+            { title: 'Writing gRPC Server', href: '/docs/advanced-guide/grpc' },
             // { title: 'Dealing with Remote Files', href: '/docs/advanced-guide/remote-files' },
             // { title: 'Supporting OAuth', href: '/docs/advanced-guide/oauth' },
-            // { title: 'Writing gRPC Server', href: '/docs/advanced-guide/grpc' },
             // { title: 'Creating a Static File Server', href: '/docs/advanced-guide/static-file-server' },
             // { title: 'WebSockets', href: '/docs/advanced-guide/websockets' },
         ],