[🚀 | Feature request]: Notify on user revoke

[mmmarcos]

What you would like to accomplish

A revoked user should receive an email notification when it is revoked from an organization.

How the feature should work

1. Alice (Administrator) revokes Bob (Member or External) from organization X.
2. Bob receives an email
   • Subject: [Parsec] You have been revoked from {Organization}
   • Body: explain what it means (permanently loose access, need for re-invite) and that it should contact an admin of the organization if it thinks there has been a mistake.