Extract Murano python jobs in a template

* Reuse template python-jobs for murano-api in layout.yaml
* Added hooks to publish Murano documentation at
  http://murano-api.readthedocs.org

Partially implements blueprint: murano-dev-doc-05

Change-Id: Ic7c64155b803230dd6562708d9af4c9d1bc64171
Merge "Extract Murano python jobs in a template"