Refs #3809 - Turning on some rubocop cops

fixes #13939 - call non-deprecated status method from API rabl

fixes #4151 - enable reports STI

Permits subclassing of ReportImporter and Report to import and store
new types of reports associated to hosts.

fixes #10832 - separating lookup keys into puppet and variable

Refs #3809 - Stabby lambda syntax for oneliners

I started by spotting log.rb which didn't have a lambda wrapping its
default scope, as needed by Rails 4. Since the style guide and most
Rails 4 documents used the stabby lambda, I turned on the cop so that we...

fixes #10933 - in api/v1 templates should be name as config_templates

fixes #10861 - Remove unused columns from the hosts table

• Serial - Never really used, probably can be refactored as kernel
  parameters.
• last_freshcheck, source_file_id - left overs from puppet old store
  configs compatibility that we no longer use, I assume no one is using...

Fixes #7096 - Adds STI to templates

This commit converts Ptables to be just another type of Template so it
gets the same features as ConfigTemplate. ConfigTemplate was renamed to
ProvisioningTemplate to reflect UI and the name under it's commonly known.

fixes #8049 - Add timezone to user

Fixes #5139 - leftovers subscribe_to_all_hostgroups

Remove user_xxx unnecessary tables and notices

Update subhostgroups removed

Fixes for migration of foreign keys

Remove users from compute_resource fixture

Remove table notices after fk are removed for pg/mysql