Reimagine channel configuration (re)loading to avoid need for git pull
Introduce a webservice responsible for providing API endpoints for:
- Fetching the stored Gerrit channel configuration (used by
wikibugs2 gerrit
) - Fetching the stored Phorge channel configuration (used by
wikibugs2 irc
) - Handling the web hook callback from GitLab to trigger an update of the stored configuration
This unlocks the ability to execute the services from a Toolforge Build Service created container while still preserving the system's ability to load new channel mappings at runtime.
Bug: T360860