Fixes #5761, #5899 - Update Katello kickstarts

This change brings the Katello kickstarts forward to match what's in the
Foreman community versions, with the community yum repos removed as Katello
will manage content.

This includes the security hardening in #5895, and Realm integration from
Fixes #6198: API methods that load database records should request only ID field.

During creation of the API search service utility, the loading of
only ID field for records being loaded from the database was incorrectly
handled. This change corrects that mistake and provides sped-up loading
times. For example, in development, a 20 item content host list was reduced
by 2-3 seconds on average.
Merge pull request #4258 from ehelms/fixes-6198

Fixes #6198: API methods that load database records should request only ...
Merge pull request #4240 from stbenjam/5761-realm-template

fixes #5761, #5899 - Update Katello kickstarts