fixes #5184 - extend foreman host to provide association to katello content host

This commit provides for a few small changes:
1. add an association to the foreman host to the katello content host
2. update the foreman defacing to use the data from this association
   versus querying the System table for the details
3. when a content host is registered, if there exists a foreman host
   with the same hostname, associate the two (host & content host)
4. with the relation added in #1, when the foreman host is deleted
   the corresponding content host will be deleted.
refs #5184 - rename 'remove' to 'unregister' for content host ui
fixes #5800 - host collections ui - errors on add/remove should be displayed
fixes #5919 - Fixes issue with katello plugin description, BZ1079191
Fixes #5574 - consider 301 as correct response for the cdn path

But check for `repodata/` instead of `repodata` as that's what we want
in the first place.
Merge pull request #4115 from bbuckingham/issue-5184

fixes #5184 - extend foreman host to provide association to katello content host
Merge pull request #4156 from iNecas/1099221

Fixes #5574 - consider 301 as correct response for the cdn path
Merge pull request #4153 from bbuckingham/issue-5800

fixes #5800 - host collections ui - errors on add/remove should be displayed
Fixes #5940/BZ1080361, show loading indicator for content view versions.
Merge pull request #4157 from waldenraines/5940

Fixes #5940/BZ1080361, show loading indicator for content view versions.
fixes #5892 - displays notification on add and delete, BZ970079
fixes #5962 - content search - fix link to manage environments
Fixes #5627: Wrapping tasks controller in new authorization.
Fixes #5863 - create consumer in plan phase

The failure is quite possible when creating a consumer in
Candlepin (mainly because of the activation key might be over-consumed
already).
Fixes #5961 - access the Dynflow world after it had been initialized
Merge pull request #4164 from iNecas/issue/5863

Fixes #5863 - create consumer in plan phase
Merge pull request #4155 from cfouant/cfouant-branch

fixes #5919 - Fixes issue with katello plugin description, BZ1079191
Merge pull request #4163 from bbuckingham/issue-5962

fixes #5962 - content search - fix link to manage environments
fixes #5954 - content search - fix puppet module details
Merge pull request #4146 from komidore64/rmi5892-custom-info-notifications

fixes #5892 - displays notification on add and delete, BZ970079