Clarify notification to "remove projects under personal accounts in Q1'2023."

[jldec]

Users with projects under their personal accounts currently see the following notification. This was introduced in #13414

We'll remove projects under personal accounts in Q1'2023.`

This should be changed so that users are not left thinking that their project data will be deleted. Suggested wording:

Projects under personal accounts have been deprecated, please add new projects under a team. Existing personal projects will continue to work for now, but may require migration to a team in future.

The docs page for projects should be also updated to include a deprecation notice. see https://github.com/gitpod-io/website/issues/2934

Example of the current notification

[gtsiolis]

Cross-posting below a relevant comment (#13414 (comment)) from the UX review in the initial PR that added this alert:

Probably not the best line to comment for this, but here's an alert we could use to inform users about projects deprecation under personal accounts. Things to consider:

1. Making the copy focus on the positive aspects of this change.
2. Nudge users with the best action forward, that is creating a team.
3. Make this closable to avoid getting into the face of users if they decide this is something they want to dismiss.

Alert to inform users about projects deprecation under personal accounts

[SamB]

Should probably actually say:

Projects under personal accounts are obsolete, please add new projects under a team. Existing personal projects will continue to work for now, but may require migration to a team in future.

with "are obsolete" in place of "have been deprecated", since it's not just a suggestion, you actually can't create new projects under personal accounts.

[gtsiolis]

This is no longer relevant as the message has been removed in #15784. Cc @svenefftinge @jldec