Add models for ContainerRegistry Sync Config

[rochacbruno]

• Add ContainerRegistryRemote as a subclass of core.Remote to hold
  configuration for syncing container repositories.
• Add the link model ContainerRegistryRepos as a one-to-many linking
  ContainerRegistryRemote to container.Remote
• Add ContainerSyncTask to save the history of sync tasks

Issue: AAH-432

Graph made with

# make api/bash
./entrypoint.sh manage graph_models \
                        -g --dot --include-models "Container*,Remote*" \
                        -o src/galaxy.dot \ 
                        core container galaxy

then

from graphviz import render
render('dot', 'png', 'galaxy.dot')

[app-sre-bot]

Can one of the admins verify this patch?

[alikins]

Kind of feels like this should live pulp_container?

Aside from basing the models from our access_policy mixins, is there anything else that makes this not suitable for pulp_container?

The need for using the access_policy mixins could be significant enough to require it in galaxy_ng, mostly asking out of curiosity.