[AEROGEAR-2374] Remove labeling task and add label to the secret instead

[JameelB]

Description

Add the serviceInstanceID label in the secret created during provision and remove the labeling task from provision.

Progress

• [x] Remove the labeling task from the provision process
• [x] Add the label serviceInstanceID to the secret created during provision

Verification Steps

• [x] Provision Aerogear UPS from the service catalog.
• [x] Verify that no labeling tasks are ran during the provision process.
• [x] Verify that the service is provisioned successfully.
• [x] Verify that the service instance has no serviceName label.
• [x] Verify that a unified-push-server secret has been created.
• [x] Verify that the label serviceInstanceID is included in this secrets yaml file.
• [x] Verify that the value of the serviceInstanceID matches with the service instance's spec.externalID value.

Additional Notes

Related JIRA Ticket - https://issues.jboss.org/browse/AEROGEAR-2374

[JameelB]

@matzew rebased :)

[psturc]

Test won't pass because there's no service instance present when you run apb test, which means that _apb_service_instance_id variable is not defined: https://jenkins-wendy.ci.feedhenry.org/blue/organizations/jenkins/AeroGearCatalog%2Funifiedpush-apb/detail/PR-30/1/pipeline#step-51-log-75

@pb82 any idea how we could solve/workaround this?