t3c should maintain onwer/group settings on config files

[jpappa200]

This Improvement request (usability, performance, tech debt, etc.) affects these Traffic Control components:

• Traffic Control Cache Config (t3c, formerly ORT)

Current behavior:

Right now t3c will only enforce config file owner/group settings when the file is written because of a change. if for some reason the owner/group is changed it will not be set back until the file contents change and is updated.

New behavior:

t3c diff will flag the file for replacement if not owned by ats or not a member of the ats group.