Install pipeline templates while the broker is provisioned

[AshishThakur]

In the current state the pipeline templates provided in template directory needs to be manually added either via spin-cli or gate-url. We need a mechanism such that all the provided templates are installed when the broker is provisioned.

[AshishThakur]

@KARTHEEKVADDE to make things simpler for this release i think we can add an step in Makefile that would iterate in the directory of the templates and install the pipelines

templates
# Call the script here.

Hence to install the template, one has to do make templates.

[AshishThakur]

and let's document that to execute the above step spincli should be installed locally and should have access to the the spinnaker.