cloud-infra: Reduce the frequency of heat based jobs to minimum

cloud-infra: Reduce the frequency of heat based jobs to minimum

Due to stability issues with CityCloud heat stack creation, we
need to limit running heat based jobs to minimum since there is
no reason anymore to run jobs automatically without hearing from
City Support first.

Here is what is done for the jobs per stack:

- ONAP Pipelines: nightly triggers for ONAP Master and ElAlto
branches have been disabled. This means that they can still be
triggered manually if needed. [0][1]
- Engine Verification Heat Jobs: voting for these jobs have been
disabled. This means that they will still be triggered when a new
patch is sent for review but their vote will not be used when
calculating the verdict. [2]
- Spinnaker Pipelines: nightly triggers for Spinnaker 1.16 pipelines
have been disabled. This means that they can still be triggered
manually if needed. [3]

[0] https://jenkins.nordix.org/job/onap-online-full-ubuntu1804-kubespray-city-cloud-daily-master/
[1] https://jenkins.nordix.org/job/onap-online-full-ubuntu1804-kubespray-city-cloud-daily-elalto/
[2] https://jenkins.nordix.org/job/cloud-infra-verify-engine-ubuntu1804-city-cloud-master/
[3] https://jenkins.nordix.org/job/k8-calico-spinnaker-ubuntu1804-kubespray-city-cloud-daily-1.16/

Change-Id: I070a38194fcf6eff17fe114c29493af2323073fc