Closes#523
This PR
- adds the three commands for `mc license` to the reference docs for
`mc`.
- Replaces `mc support register` with `mc license register`.
- Updates references to `mc support register` to point to `mc license
register` instead.
This adds content to the three stub files.
Corrects the Makefile for incorrect importing of Javascript docs into the Haskell folder.
Corrects community Slack URLs to point to slack.min.io.
