Add Team Drive model and basic fetch.

Summary:
Add Team Drive model, basic fetch (no File search query string) and fetch test.
Add Team Drive usage example that allows listing Team Drives and their contents (very crude). Uses teamdrivefetchjob and filefetchjob.

Test Plan: See provided example in examples/teamdrive.

Reviewers: dvratil

Reviewed By: dvratil

Subscribers: kde-pim, #libkgapi

Tags: #libkgapi, #kde_pim

Maniphest Tasks: T10521

Differential Revision: https://phabricator.kde.org/D19403