[feature] Improved thumbs up bot

[nikgil]

Is your feature request related to a problem? Please describe

Reference comment: #140 (comment)

Basically make the thumbs up bot more expansive to different channels

Describe the solution you'd like

This breaks down to the following:

• command to add channel to thumbs up bot
• command to remove channel from thumbs up bot
• purge inactive channels (in case some get deleted)
• Keep tally per channel of most upvoted (possible trigger in add channel field if we need to maintain tally)
• purge tallies if needed (if they aren't needed in the list, channel axed, etc)

Describe alternatives you've considered

Current bot in dev only does a simple thumbs up in event questions channel and no tallies

Additional context

The tasks should be done in separate PRs to make it not bulky and then remove env for event questions channel as it'll be in DB