Add mention bot
Add mention bot

In order to deploy https://github.com/facebook/mention-bot it's good to
have a .mention-bot file in the root directory.

This PR adds that said file as well as creates a user blacklist so
maintainer alumni aren't needlessly pinged.

cdrage/kompose,ashetty1/kompose,surajnarwade/kompose,rupalibehera/kompose,skippbox/kompose,procrypt/kompose,surajnarwade/kompose,kubernetes/kompose,kadel/kompose,surajnarwade/kompose,procrypt/kompose,kadel/kompose,ashetty1/kompose,ashetty1/kompose,skippbox/kompose,kubernetes/kompose,rupalibehera/kompose,rupalibehera/kompose,procrypt/kompose,cdrage/kompose,skippbox/kompose