Allow User Notes to Be Left on Users in the Gitpod Admin UI

Is your feature request related to a problem? Please describe

When looking up reasons on why an account has marked as blocked it seems it can sometimes be found in Slack and other times not. Instead of whomever has blocked the account dropping a link into Slack I believe there would be more benefit to just keeping it all within the account in Gitpod.

This could likely be used for reason beyond just leaving notes on why a user was blocked as well, but any notes related the account.

Describe the behaviour you'd like

I would like to see that when the Block User button is clicked on a modal pops up and asks for the blocker to either select from a list of preset reasons or probably better require them to leave a note with the id of the workspace that caused the user to get blocked and what the reason was.

Describe alternatives you've considered

Right now, just hoping that whomever blocked the user also left a message in Slack with the workspace id and reason.

Additional context

N/A

Start by locating the Gitpod Admin UI flow for blocking a user and the existing block-user modal or action. Define how notes or preset reasons should be stored and displayed, including the workspace ID and blocking reason. Done means an administrator can enter the relevant information when blocking a user and later find it on that user's account.