refactor: extract userbot to standalone repo, add as git submodule

userbot now lives at ssh://git@gitssh.forust.xyz:2221/forust/userbot.git
and is included in homelab as a submodule at userbot/

userbot/.dockerignore

@@ -1,12 +0,0 @@
-.unused
-Downloads
-.venv
-volumes
-.env
-.env.*
-my_account.session
-.gitignore
-README.md
-.git
-uv.lock
-.deepsource.toml