Backup & Restore: Prevent backup from proceeding if portieris is enabled

[Ghada Khalil]

Brief Description
-----------------
Currently, if a user does a backup & restore with the portieris application enabled, the restore fails as per LP: https://bugs.launchpad.net/starlingx/+bug/1890630 and the system is left in a bad state.

As a short term solution, the backup should return an error asking the user to remove the application before proceeding.

Severity
--------
Minor

Steps to Reproduce
------------------
See https://bugs.launchpad.net/starlingx/+bug/1890630 for steps

Expected Behavior
------------------
The backup should be rejected asking the user to remove the poertieris app

Actual Behavior
----------------
State what is the actual behavior

Reproducibility
---------------
Reproducible

System Configuration
--------------------
any

Branch/Pull Time/Commit
-----------------------
stx master as of 2020-08-04_20-00-00

Last Pass
---------
Never - new test-case

Timestamp/Logs
--------------
N/A

Test Activity
-------------
Feature Testing

Workaround
----------
Remove the portieris application before starting the backup:
system application-remove portieris
kubectl delete clusterroles.rbac.authorization.k8s.io portieris

kubectl delete clusterrolebindings.rbac.authorization.k8s.io admission-portieris-webhook

kubectl delete -n portieris secret/portieris-certs

kubectl delete -n portieris cm/image-policy-crds
kubectl delete -n portieris serviceaccounts/portieris

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/747327

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/747327
Committed: https://git.openstack.org/cgit/starlingx/ansible-playbooks/commit/?id=888fa40a23433198d7e882708c957af0eab37585
Submitter: Zuul
Branch: master

commit 888fa40a23433198d7e882708c957af0eab37585
Author: Joseph Richard <email address hidden>
Date: Thu Aug 20 23:46:03 2020 -0400

    Block system backup when portieris applied

    B&R is not currently supported with portieris installed, due to webhook
    blocking mutating pods, while portieris pods can't run because the
    local registry has not been populated yet.

    Block until a fix is implemented.

    Closes-bug: 1891730
    Change-Id: I42d70b7da1fdd29c33abf5a977d36c55bab901fb
    Signed-off-by: Joseph Richard <email address hidden>