aurweb.spawn: Integrate FastAPI and nginx

aurweb.spawn used to launch only PHP’s built-in server. Now it spawns a
dummy FastAPI application too. Since both stacks spawn their own HTTP
server, aurweb.spawn also spawns nginx as a reverse proxy to mount them
under the same base URL, defined by aur_location in the configuration.

Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>

aurweb/asgi.py

@@ -0,0 +1,8 @@
+from fastapi import FastAPI
+
+app = FastAPI()
+
+
+@app.get("/hello/")
+async def hello():
+    return {"message": "Hello from FastAPI!"}