feat: add create user group

[rek]

Add API for Teams: user groups

Link to ClickUp docs: https://clickup.com/api/clickupreference/operation/CreateTeam/

• [x] Add Create
• [x] Add Update
• [x] Add Delete
• [x] Add tests for Create
• [x] Add tests for Update
• [x] Add tests for Delete
• [x] Update Doc

Closes #51

[rek]

@w-haibara this one is ready for review whenever you are free :D