Add #governance discord channel

Create a #governance channel in the Optimism Fractal discord for discussions, announcements and proposals related to Optimism Fractal governance.

Currently much of this is happening in the #general channel and it is frequent enough to warrant its own channel. This would free up space in the #general channel for a greater diversity of posts and topics.

Examples of specific types of things that can be posted in the #governance channel: Respect Game event invites & updates, links to active proposals, discussion on active proposals, general governance thoughts & questions etc.

Passing this proposal would signal the desire by the community to make a #governance channel in the Discord.