Adds the client functionality for the following project tag calls:
- Create a project tag on a project
- Check if a project tag exists on a project
- List project tags on a project
- Modify project tags on a project
- Delete a specific project tag on a project
- Delete all project tags on a project
Co-Authored-By: Jess Egler <jess.egler@gmail.com>
Co-Authored-By: Rohan Arora <ra271w@att.com>
Co-Authored-By: Tin Lam <tin@irrational.io>
Partially Implements: bp project-tags
Change-Id: I486b2969ae0aa2638842d842fb8b0955cc086d25
9cfbf96620