Update repository importer to use new Bitbucket Cloud workspace API

Issue Summary

The repository importer relies on APIs which are being deprecated as part of Bitbucket Cloud's work on shifting to their new Workspaces API. 

• https://developer.atlassian.com/cloud/bitbucket/bitbucket-api-teams-deprecation/
• https://developer.atlassian.com/cloud/bitbucket/bitbucket-api-changes-workspaces/

Without updating to the new workspaces API it will not be possible to import Bitbucket cloud repositories once these APIs are removed.

Steps to Reproduce

1. Try to import a Bitbucket cloud repository

Expected Results

Import is successful.

Actual Results

The request to receive workspaces associated with the user specified will fail.

Workaround

Upgrade to a version of Bitbucket that is using Workspace APIs