Use Starlette, uvicorn and websockets; rename Docker files to container ones

Serve neo4j-browser with Starlette and uvicorn (the optional browser extra)
instead of a hand-written HTTP server, and handle Bolt over WebSocket with the
websockets library's Sans-I/O protocol. Rename Dockerfile, .dockerignore and
docker/ to Containerfile, .containerignore and container/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.containerignore

@@ -0,0 +1,9 @@
+.git
+**/__pycache__
+**/*.pyc
+.venv
+tests
+**/build
+**/dist
+**/*.egg-info
+.idea