Feature suggestion: add link to invidious

I think this is a great bot ! I had given up on linking to Invidious directly, because the service is being chased down and sites can be unstable.

In addition to the Piped link, this bot could also have a link to redirect.invidious.io. This way, people can pick their preferred front end.

Note that invidious can't handle the format `/<video-id>` and needs `/watch?v=<video-id>` instead.