Fixes #7947 - Validating package checksums when syncing

Check the package checksums after they are synced. This will tell if packages
are corrupt, partially downloaded, etc. Decided to make a config option to
disable it too as checking decreased the performance of the sync by about 40%
(observed 1 hr 12 min without validation for a RHEL 6server kickstart repo and
1 hr 40 min for the same repo but with the checksum validation enabled).
fixes #8087 - Locations - update to allow proper use of nested locations

Without this commit, the user can click 'Nest' to created a nested
location; however, they cannot actually assign a parent location.
As a result, nesting really isn't functional.

This commit will conditionally remove the 'parent' for organization
taxonomies, but leave them in place on the location taxonomies.

This can be tested using the following:
- new & edit org - confirm there is no 'parent'
- new, edit, nest location - confirm that user can select a 'parent'
fixes #8089 - Content Dashboard - fix the sorting of items in Sync Overview
Merge pull request #4764 from bbuckingham/issue-8089

fixes #8089 - Content Dashboard - fix the sorting of items in Sync Overview
Merge pull request #4763 from bbuckingham/issue-8087

fixes #8087 - Locations - update to allow proper use of nested locations
Merge pull request #4747 from daviddavis/temp/20141014174658

Fixes #7947 - Validate package checksums when syncing
Fixes #7951 - Add/Remove Docker repos to Content Views

One can now add/remove docker based repos to content views.
Merge pull request #4758 from parthaa/cv-ui

Fixes #7951 - UI - Add/Remove Docker repos to Content Views