feat: implement draft for a Nest.js SDK (#718)

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## This PR
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This is a first draft of a Nest.js SDK.
Currently it only handles injecting clients and feature flags.
I also added a context factory for the FeatureFlag decorators to be able
to use request information for the execution context.

### Related Issues
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Fixes #705 

### Notes
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@toddbaert maybe we can do it as we did with the React SDK, merge this
fast and release as experimental to let people experiment and try out?

### Follow-up Tasks
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noted under this section -->
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We will have to see if we want to stick with the injected feature flags
being wrapped in an observable.
To me this feels the most idiomatic for Nest.js.

### How to test
Tests for the current functionality are included.

---------

Signed-off-by: Lukas Reining <[email protected]>
Co-authored-by: Henry Chen <[email protected]>
Co-authored-by: Luiz Guilherme Ribeiro <[email protected]>
Co-authored-by: Todd Baert <[email protected]>

Author: 4 people

.release-please-manifest.json

@@ -1,4 +1,5 @@
 {
+  "packages/nest": "0.0.1-experimental",
   "packages/react": "0.0.5-experimental",
   "packages/client": "0.4.8",
   "packages/server": "1.7.5",

jest.config.ts

@@ -120,7 +120,7 @@ export default {
       preset: 'ts-jest',
       testMatch: ['<rootDir>/packages/server/test/**/*.spec.ts'],
       moduleNameMapper: {
-        '@openfeature/core': '<rootDir>/packages/shared/src'
+        '@openfeature/core': '<rootDir>/packages/shared/src',
       },
     },
     {
@@ -129,8 +129,8 @@ export default {
       preset: 'ts-jest',
       testMatch: ['<rootDir>/packages/client/test/**/*.spec.ts'],
       moduleNameMapper: {
-        '@openfeature/core': '<rootDir>/packages/shared/src'
-      }
+        '@openfeature/core': '<rootDir>/packages/shared/src',
+      },
     },
     {
       displayName: 'server-e2e',
@@ -140,7 +140,7 @@ export default {
       modulePathIgnorePatterns: ['.*/node-modules/'],
       setupFiles: ['<rootDir>/packages/server/e2e/step-definitions/setup.ts'],
       moduleNameMapper: {
-        '@openfeature/core': '<rootDir>/packages/shared/src'
+        '@openfeature/core': '<rootDir>/packages/shared/src',
       },
     },
     {
@@ -153,7 +153,24 @@ export default {
       moduleNameMapper: {
         '^uuid$': require.resolve('uuid'),
         '^(.*)\\.js$': ['$1', '$1.js'],
-        '@openfeature/core': '<rootDir>/packages/shared/src'
+        '@openfeature/core': '<rootDir>/packages/shared/src',
+      },
+    },
+    {
+      displayName: 'nest',
+      testEnvironment: 'node',
+      preset: 'ts-jest',
+      testMatch: ['<rootDir>/packages/nest/test/**/*.spec.ts'],
+      moduleNameMapper: {
+        '@openfeature/core': '<rootDir>/packages/shared/src',
+      },
+      transform: {
+        '^.+\\.ts$': [
+          'ts-jest',
+          {
+            tsconfig: '<rootDir>/packages/nest/tsconfig.spec.json',
+          },
+        ],
       },
     },
   ],