✨ Re-export utils from Starlette (#1064)

* ✨ Re-export main features used from Starlette to simplify developer's code

* ♻️ Refactor Starlette exports

* ♻️ Refactor tutorial examples to use re-exported utils from Starlette

* 📝 Add examples for all middlewares

* 📝 Add new docs for middlewares

* 📝 Add examples for custom responses

* 📝 Extend docs for custom responses

* 📝 Update docs and add notes explaining re-exports from Starlette everywhere

* 🍱 Update screenshot for HTTP status

* 🔧 Update MkDocs config with new content

* ♻️ Refactor tests to use re-exported utils from Starlette

* ✨ Re-export WebSocketDisconnect from Starlette for tests

* ✅ Add extra tests for extra re-exported middleware

* ✅ Add tests for re-exported responses from Starlette

* ✨ Add docs about mounting WSGI apps

* ➕ Add Flask as a dependency to test WSGIMiddleware

* ✅ Test WSGIMiddleware example

tests/test_tutorial/test_sql_databases/test_sql_databases.py

@@ -1,7 +1,7 @@
 from pathlib import Path
 
 import pytest
-from starlette.testclient import TestClient
+from fastapi.testclient import TestClient
 
 openapi_schema = {
     "openapi": "3.0.2",

tests/test_tutorial/test_sql_databases/test_sql_databases_middleware.py

@@ -1,7 +1,7 @@
 from pathlib import Path
 
 import pytest
-from starlette.testclient import TestClient
+from fastapi.testclient import TestClient
 
 openapi_schema = {
     "openapi": "3.0.2",