stx-openstack: conditional usage of neutron service_plugin

[Rafael Falcão]

Brief Description
-----------------
The 0016-Network-Resources-Cleanup-before-OpenStack-Removal patch scripts requires some neutron service_plugin (e.g trunk) to be enabled. If any plugin is not enabled, the removal of stx-openstack will get stuck in the remove_failed status. An conditional check of the existence of all required plugins needs to take place to avoid the remove_failed issue.

Severity
--------
Provide the severity of the defect.
Minor

Steps to Reproduce
------------------
- Remove 'trunk' as neutron's service_plugin
- Try to remove stx-openstack application

Expected Behavior
------------------
stx-application reaches 'uploaded' status

Actual Behavior
----------------
stx-application reaches 'remove_failed' status

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

System Configuration
--------------------
NA

Timestamp/Logs
--------------
/var/log/armada/<deletion-log>
2022-07-19 10:05:35.100 262 ERROR armada.cli armada.exceptions.tiller_exceptions.ReleaseException: Failed to Delete release: osh-openstack-neutron - Tiller Message: b'Install complete'

kubectl logs -f -c tiller -n armada <armada-pod>
[tiller] 2022/07/19 10:51:42 warning: Release osh-openstack-neutron pre-delete neutron/job-resources-cleanup.yaml could not complete: Job failed: BackoffLimitExceeded
[tiller] 2022/07/19 10:51:42 deleting pre-delete hook neutron-resources-cleanup for release osh-openstack-neutron due to "hook-failed" policy

Test Activity
-------------
Developer testing

Workaround
----------
Add all required service_plugins previously the stx-openstack removal