Fixes #5821 - Capsule Content API/Backend
Fixes #5821 - Remove the fort engine

The code now uses mainly the Foreman's proxy logic + additional
support in Katello itself: not need to maintain separate engine just
for the node syncing
Fixes #5821 - address PR review issues
fixes #5857 - enclose sub-mgr args in quotes
Fixes #5821 - add tests for capsule related features
Fixes #5821 - fix binding repository to the node
Fixes #5821 - add capsule content authorization
Fixes #5821 - add capsule content authorization tests
Fixes #5768 Changed term system to content-host
updated all references from system to content host
Fixes #5821 - better graceful handling of node binding/unbinding
fixes #5819 - host groups - fix the cross-link to activation keys page

This is a change needed after the 'single-page-app' changes went in.
Merge pull request #4143 from bbuckingham/issue-5819

fixes #5819 - host groups - fix the cross-link to activation keys page
Merge pull request #4118 from iNecas/capsule-api

add capsule support to API/CLI
Merge pull request #4144 from jlsherrill/iNecas-capsule-api

Fixes #5821 - add capsule support to API/CLI
Fixes #5886: Return organizations for the admin user.

Since the admin user is treated differently than other users, the
admin user doesn't have a direct relationship to any organizations.
Thus, we need to check if the user is an admin and return all
organizations.
Fixes #5526: Ensure content APIs are properly permission wrapped.

Intent is for packages, errata, package groups, and distributions the
user has :view_products and can then see the content for any products/repos
they have access to. For content within a content view, the user needs
:view_content_views permission.

For repository sets, a user needs :view_subscriptions to show, index or
see available repository sets and :import_manifest in order to disable/enable.
Merge pull request #4131 from thomasmckay/5857-snippet

fixes #5857 - enclose sub-mgr args in quotes
Merge pull request #4141 from ehelms/fixes-5886

Fixes #5886: Return organizations for the admin user.
Merge pull request #4139 from cfouant/cfouant-branch

Fixes #5768 Changed term system to content-host