feat: sync conversations between gus and git

[mohanraj-r]

Once the WI gets created for the GH issue, we now have 2 distinct places that we can have conversations about the work - which could be cumbersome to keep track of etc. It would be great if we can sync conversations in the GUS WI chatter to the GH issue and vice versa based on an opt-in tag e.g.

[uip-robot-zz]

Git2Gus App is installed but the .git2gus/config.json doesn't exist.

[randi274]

Would you expect it to create a new thread or add to the existing message that gets logged @mohanraj-r?

[mohanraj-r]

@randi274 That is going to be tricky as GH issues doesn't have threads but you can quote and reply.
To keep it simple I guess we can create a new thread for each message.
A related feat req would be to have config mapping GH usernames to gus usernames so the bot can post as the gus user or at least mention the gus user when posting the message.