Clickup Import

Linking existing issues from Clickup is OK (although it's currently not working, see separate bug).

But in our case, when we start with a project we often have existing Clickup backlogs of ~100 issues. So in a first setup step we would meed to copy and link all of them into Featurebase automatically.

This feature req may apply to other integrations as well.

Proposed solution:

1. User clicks on "Import from Clickup"

2. Fb presents a list of non-linked issues from the Clickup list(s) that have been configured

3. User selects the desired clickup issues using checkboxes, or selects ALL

4. User clicks "Import"

5. Fb creates a post per selected clickup issue and also links them.

6. User can now manually fine-tune the content of the imported posts (change description/title to make it more compatible for the general public)