[ussuri][goal] Update contributor documentation

This patch updates/adds the contributor documentation to follow
the guidelines of the Ussuri cycle community goal[1].

[1] https://governance.openstack.org/tc/goals/selected/ussuri/project-ptl-and-contrib-docs.html

Story: #2007236
Task: #38524
Change-Id: I9672ee1011b06b86ba4df331cd1149a18bc1f408

CONTRIBUTING.rst

@@ -0,0 +1,19 @@
+The source repository for this project can be found at:
+
+   https://opendev.org/openstack/heat-agents
+
+Pull requests submitted through GitHub are not monitored.
+
+To start contributing to OpenStack, follow the steps in the contribution guide
+to set up and use Gerrit:
+
+   https://docs.openstack.org/contributors/code-and-documentation/quick-start.html
+
+Bugs should be filed on Storyboard,:
+
+   https://storyboard.openstack.org/#!/project/openstack/heat-agents
+
+For more specific information about contributing to this repository, see the
+heat-agents contributor guide:
+
+   https://docs.openstack.org/heat-agents/latest/contributor/contributing.html

doc/source/contributor/contributing.rst

@@ -0,0 +1,47 @@
+============================
+So You Want to Contribute...
+============================
+For general information on contributing to OpenStack, please check out the
+`contributor guide <https://docs.openstack.org/contributors/>`_ to get started.
+It covers all the basics that are common to all OpenStack projects: the accounts
+you need, the basics of interacting with our Gerrit review system, how we
+communicate as a community, etc.
+Below will cover the more project specific information you need to get started
+with heat-agents.
+
+Communication
+~~~~~~~~~~~~~
+* IRC channel #heat at OFTC
+* Mailing list (prefix subjects with ``[heat]`` for faster responses)
+  http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-discuss
+
+Contacting the Core Team
+~~~~~~~~~~~~~~~~~~~~~~~~
+Please refer the `heat-agents Core Team
+<https://review.opendev.org/admin/groups/b4b16f97f2b8416cb0111c0bec5df885bd779347,members>`_ contacts.
+
+New Feature Planning
+~~~~~~~~~~~~~~~~~~~~
+heat-agents features are tracked on `Storyboard <https://storyboard.openstack.org/#!/project/openstack/heat-agents>`_.
+
+Task Tracking
+~~~~~~~~~~~~~
+We track our tasks in `Storyboard <https://storyboard.openstack.org/#!/project/openstack/heat-agents>`_.
+If you're looking for some smaller, easier work item to pick up and get started
+on, search for the 'low-hanging-fruit' tag.
+
+Reporting a Bug
+~~~~~~~~~~~~~~~
+You found an issue and want to make sure we are aware of it? You can do so on
+`Storyboard <https://storyboard.openstack.org/#!/project/openstack/heat-agents>`_.
+
+Getting Your Patch Merged
+~~~~~~~~~~~~~~~~~~~~~~~~~
+All changes proposed to the heat-agents project require one or two +2 votes
+from heat-agents core reviewers before one of the core reviewers can approve
+patch by giving ``Workflow +1`` vote.
+
+Project Team Lead Duties
+~~~~~~~~~~~~~~~~~~~~~~~~
+All common PTL duties are enumerated in the `PTL guide
+<https://docs.openstack.org/project-team-guide/ptl.html>`_.

doc/source/index.rst

@@ -25,3 +25,13 @@ supplied configuration data, and return any outputs back to Heat.
    :maxdepth: 3
 
    install/index
+
+For Contributors
+================
+
+* If you are a new contributor to heat-agents please refer: :doc:`contributor/contributing`
+
+  .. toctree::
+     :hidden:
+
+     contributor/contributing