Fixes #5408, display errors on new sync plan form.
Fixes #5198 - make bastion a true single page application.

This PR changes all bastion pages to be served as a single page
from / instead of multiple pages served from /katello/<resource>.
This will speed up load time between the pages (since we won't
have to reload the entire page for each Bastion page).
fixes #5511 - renamed create_unlimited_supscription.rb
Fixes #5508, allow alch-checkbox display values to be formatted.
Fixes #5495 - Validate content urls for ISO repositories
Fixes #5037 - Enable ISO repo sets from a manifest
Fixes #5515, adding Bastion config directory to whitelist for RPMs.
Fixes #5504: Consolidates Katello about page information to the Foreman about page.

Removes the Katello about page and uses deface to add two status widgets
to the Foreman about page. The two widgets are the backend status information
for services such as Pulp and Candlepin and a widget that lists installed packages.
fixes 5512 - fixing content view delete performance issues
Fixes #5008 Manifest History not updated on import

- importing/deleting/reloading manifest file also triggers update/display of manifest
  history
- BZ1077893
- exposes import history in subscriptions v2 api