✨ Auto-generate OpenAPI servers from root_path (#1596)

* root_path included in servers object instead of path prefix

* ♻️ Refactor implementation of auto-including root_path in OpenAPI servers

* 📝 Update docs and examples for Behind a Proxy, including servers

* 📝 Update Extending OpenAPI as openapi_prefix is no longer needed

* ✅ Add extra tests for root_path in servers and root_path_in_servers=False

* 🍱 Update security docs images with relative token URL

* 📝 Update security docs with relative token URL

* 📝 Update example sources with relative token URLs

* ✅ Update tests with relative tokens

Co-authored-by: Sebastián Ramírez <tiangolo@gmail.com>

docs_src/extending_openapi/tutorial001.py

@@ -9,7 +9,7 @@ async def read_items():
     return [{"name": "Foo"}]
 
 
-def custom_openapi(openapi_prefix: str):
+def custom_openapi():
     if app.openapi_schema:
         return app.openapi_schema
     openapi_schema = get_openapi(
@@ -17,7 +17,6 @@ def custom_openapi(openapi_prefix: str):
         version="2.5.0",
         description="This is a very custom OpenAPI schema",
         routes=app.routes,
-        openapi_prefix=openapi_prefix,
     )
     openapi_schema["info"]["x-logo"] = {
         "url": "https://fastapi.tiangolo.com/img/logo-margin/logo-teal.png"