Community: Gitter <-> Matrix <-> Discord integration

[sitiom]

Related to #3240

Feature Request

Is your feature request related to a problem? Please describe.

Matrix is a great way to unify various other chat platforms via bridges. And for some time now, Gitter has become Matrix native. We can now then connect Scoop's Discord server to the Matrix Room to leverage the benefit of Gitter's indexable public message history (See Discord is a black hole for information.).

Describe the solution you'd like

See https://github.com/elves/elvish. They were able to set it up successfully with a Gitter <-> Matrix <-> Telegram integration. Discord isn't anything different. #4829 would have to be solved first.