How can we manage the tags in ticket

How can we manage the tags in ticket

Allowing agents to use Tags indiscriminately can cause havoc. We could not find tag management where 

1. The admin can create Tags beforehand for use by Agents
2. Permission can be allocated which roles/profiles can use existing tags or add new tags
3. Admin can see all tags and bulk delete / bulk rename them

Without these management functions "tags" will be indiscriminately used and very soon reach a chaotic state.

Do you have a solution?