Support offline restore on proxy deployments

[sjha4]

Why are you introducing these changes? (Problem description, related links)

Support offline restore on proxies. Built on top of offline restore commit hence marking draft.

What are the changes introduced in this pull request?

• Adds some proxy specific logic to offline restore to be able to run against proxy deployments.

How to test this pull request

1. Set up a proxy
2. Run foremanctl backup /tmp/backup --target-host proxy
3. Run foremanctl restore /tmp/backup/backup_dir --target-host proxy --force

Checklist

• Tests added/updated (if applicable)
• Documentation updated (if applicable)

[sjha4]

In first read of the PR, this should work with #611 with this so we can claim proxy backup-restore really brings proxy to backed up state. Otherwise we'll require a complete proxy sync after restore to handle container gateway. I'll test both PRs together and see if we need any updates.

[sjha4]

I did some testing of this with Cheyenne's restore PR and Ian's container_gateway PR with this. Was able to backup container_gateway DB and restore the DB and redeploy proxy with correct features, content and container_gateway. Will keep this in draft till the restore PR goes in so the commits can be cleaned up.

Backup on proxy with pulp and container_gateway

TASK [backup : Display backup completion] ********************************************************************************************************
ok: [localhost] => 
    msg: |-
        Backup completed successfully.
        Location: /tmp/backup/foreman-backup-20260723T130214
        Databases: pulp, container_gateway

Restore validate:

TASK [restore : Verify database dump files exist] ************************************************************************************************
ok: [localhost] => (item=pulp)
ok: [localhost] => (item=container_gateway)

Restore:

TASK [restore : Build database restore configuration] ********************************************************************************************
ok: [localhost] => (item=pulp)
ok: [localhost] => (item=container_gateway)

TASK [restore : Verify dump files exist] *********************************************************************************************************
ok: [localhost] => (item=pulp.dump)
ok: [localhost] => (item=container_gateway.dump)

TASK [restore : Drop existing databases] *********************************************************************************************************
changed: [localhost] => (item=pulp)
changed: [localhost] => (item=container_gateway)

TASK [restore : Create empty databases] **********************************************************************************************************
changed: [localhost] => (item=pulp)
changed: [localhost] => (item=container_gateway)

TASK [restore : Enable postgres_fdw extension for IOP databases] *********************************************************************************
skipping: [localhost] => (item=pulp) 
skipping: [localhost] => (item=container_gateway) 
skipping: [localhost]

TASK [restore : Restore databases from dump files] ***********************************************************************************************
changed: [localhost] => (item=pulp.dump → pulp)
changed: [localhost] => (item=container_gateway.dump → container_gateway)