FEATURE: Add Rebase Workspace button to Workspace UI

[pKallert]

I added a rebase button to the new workspaces module.

The button is shown if the Workspace is updated

The happy path is clicking the button and rebasing the workspace:

The not-happy path will show a popup:

If this does not work, an error will be shown. If it works, a success message will be shown.

Checklist

• Code follows the PSR-2 coding style
• Tests have been created, run and adjusted as needed
• The PR is created against the lowest maintained branch
• Reviewer - PR Title is brief but complete and starts with FEATURE|TASK|BUGFIX
• Reviewer - The first section explains the change briefly for change-logs
• Reviewer - Breaking Changes are marked with !!! and have upgrade-instructions

[mhsdesign]

Funzt perfecto danke