[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: #38554

Change-Id: Ifdbebe6fe4679a1a7af65e671746c98fe06d19fd

CONTRIBUTING.rst

@@ -1,85 +1,19 @@
-OpenStack horizon
+The source repository for this project can be found at:
-#################
-:tags: openstack, horizon, cloud, ansible
-:category: \*nix
 
-contributor guidelines
+  https://opendev.org/openstack/openstack-ansible-os_horizon
-^^^^^^^^^^^^^^^^^^^^^^
 
-Filing Bugs
+Pull requests submitted through GitHub are not monitored.
------------
 
-Bugs should be filed on Launchpad, not GitHub: "https://bugs.launchpad.net/openstack-ansible"
+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
 
-When submitting a bug, or working on a bug, please ensure the following criteria are met:
+Bugs should be filed on Launchpad:
-    * The description clearly states or describes the original problem or root cause of the problem.
-    * Include historical information on how the problem was identified.
-    * Any relevant logs are included.
-    * The provided information should be totally self-contained. External access to web services/sites should not be needed.
-    * Steps to reproduce the problem if possible.
 
+   https://bugs.launchpad.net/openstack-ansible
 
-Submitting Code
+For more specific information about contributing to this repository, see the
----------------
+openstack-ansible contributor guide:
 
-Changes to the project should be submitted for review via the Gerrit tool, following
+    https://docs.openstack.org/openstack-ansible/latest/contributor/contributing.html
-the workflow documented at: "https://docs.openstack.org/infra/manual/developers.html#development-workflow"
-
-Pull requests submitted through GitHub will be ignored and closed without regard.
-
-
-Extra
------
-
-Tags:
-    If it's a bug that needs fixing in a branch in addition to Master, add a '\<release\>-backport-potential' tag (eg ``juno-backport-potential``). There are predefined tags that will autocomplete.
-
-Status:
-    Please leave this alone, it should be New till someone triages the issue.
-
-Importance:
-    Should only be touched if it is a Blocker/Gating issue. If it is, please set to High, and only use Critical if you have found a bug that can take down whole infrastructures.
-
-
-Style guide
------------
-
-When creating tasks and other roles for use in Ansible please create then using the YAML dictionary format. 
-
-Example YAML dictionary format:
-    .. code-block:: yaml
-
-        - name: The name of the tasks
-          module_name:
-            thing1: "some-stuff"
-            thing2: "some-other-stuff"
-          tags:
-            - some-tag
-            - some-other-tag
-
-
-Example **NOT** in YAML dictionary format:
-    .. code-block:: yaml
-
-        - name: The name of the tasks
-          module_name: thing1="some-stuff" thing2="some-other-stuff"
-          tags:
-            - some-tag
-            - some-other-tag
-
-
-Usage of the ">" and "|" operators should be limited to Ansible conditionals and command modules such as the ansible ``shell`` module.
-
-
-Issues
-------
-
-When submitting an issue, or working on an issue please ensure the following criteria are met:
-    * The description clearly states or describes the original problem or root cause of the problem.
-    * Include historical information on how the problem was identified.
-    * Any relevant logs are included.
-    * If the issue is a bug that needs fixing in a branch other than Master, add the 'backport potential' tag TO THE ISSUE (not the PR).
-    * The provided information should be totally self-contained. External access to web services/sites should not be needed.
-    * If the issue is needed for a hotfix release, add the 'expedite' label.
-    * Steps to reproduce the problem if possible.