New Project page should show message and link to /workspaces when authorized only with Bitbucket

[gtsiolis]

Bug description

Teams & Projects rolled out with support for GitLab and GitHub projects. The natural next step here is to add support for adding projects from Bitbucket.org git provider, see #5980.

However, if you have a Gitpod account that is only connected with a Bitbucket account, adding a project is not possible, see screenshot below.

Steps to reproduce

1. Create an account on Gitpod with Bitbucket
2. Try adding a project

Workspace affected

No response

Expected behavior

Instead of the error while showing loading, show the following message

We are still working working on Bitbucket support for Projects.
Continue to workspaces, or login with GitHub or GitLab to use Projects.

This ☝️ is a variant of what was proposed originally. 👇 -- thanks @gtsiolis

Possibly, if we move forward with fixing this before #5980, we could redirect to an error page and informing the user to connect a supported git provider for adding projects. 💡 ~~

Example repository

No response

Anything else?

No response

[jldec]

/schedule

[JanKoehnlein]

/assign

[JanKoehnlein]

To test it, we have to re-enable Bitbucket auth on core-dev. Waiting for team platform to deploy the new secrets