Changes to support new lobby server

[myndzi]

Includes migration and integration changes to support using https://github.com/noita-together/lobby-server as the backend lobby server:

• Switch to protobuf-es; it's slower to serialize/deserialize, but significantly more correct, and the main performance bottleneck is addressed at the server level
• Docker build is changed to run only the web frontend, instead of both the web frontend and the lobby server under pm2
• PlayerPosition vs PlayerMove is handled in the client now instead of the server (future work: go back to server-handling and see under real load if it is a regression; synthetic load testing locally suggested this is a slight improvement)
• Fixes the NT app not displaying the current seed from UpdateFlags (and, more generally, should handle flag value types other than boolean)
• Environment variable configuration is clearer; support SNI
• Includes Skye's changes to serve stats from the lobby-server's API
• New health-check on the web frontend to test if the backend is available

With this code, new environment variables should be used to build the client: nt-app/.env -

VUE_APP_NT_LOGIN_URL=https://noitatogether.com/api/auth/login
VUE_APP_LOBBY_SERVER_WS_URL_BASE=wss://lobby.noitatogether.com/ws
NEXT_PUBLIC_LOBBY_SERVER_API_URL_BASE=https://lobby.noitatogether.com/api

[myndzi]

Let's wait until at least one playtest confirms nothing is heinously wrong, but this should otherwise be ready to go. The current production servers are running this version of the code, so the old "NT Beta" client is currently going to fail until users download this version, or I revert all the server changes. A new release will have to be created and uploaded.

r? @SkyeOfBreeze