Deprecation of BitbucketCloud teams permissions endpoint

[nabokihms]

Is your feature request related to a problem?

BitbucketCloud API endpoint /user/permissions/teams became deprecated, though we had decided to use it to get user groups (#1811).

Describe the solution you'd like to see

The only way of solving the problem, which I see, is switching to workplaces as the source for dex groups.

1. Change the teams API endpoint to the workspaces API endpoint in our code.
2. Throw deprecation warning if the teams option is used in provider settings.
3. Add a new option - workspaces to filter groups.
4. Allow specifying only one of the options from above.

Describe alternatives you've considered

The only alternative is waiting for the deletion of the deprecated endpoint.

Additional context

Oh, looks like we undoubtfully need to move some connectors out of the main repo...

[nabokihms]

closed in favour of #2390