docs.voltha.org::HOWTO edits and WARNING cleanups.

Makefile
--------
  o Added convenience target 'make warnings' to help search for problems.

config.py
---------
  o Add more exclusions for .venv/ so sphinx will stop checking sources.

howto/edit_voltha_docs.rts
howto/docs.voltha.org/index.rst
howto/docs.voltha.org/quickstart.rst
howto/docs.voltha.org/edit_voltha_docs.rst
------------------------------------------
  o Added a quickstart guide for editing repo:voltha-docs

Misc
----
  o Fixed several WARNINGS
  o Add missing documents in index.rst

Change-Id: I0b3d01cc4116d40bd84db49649669253d6135546
diff --git a/howto/docs.voltha.org/quickstart.rst b/howto/docs.voltha.org/quickstart.rst
new file mode 100644
index 0000000..25743fe
--- /dev/null
+++ b/howto/docs.voltha.org/quickstart.rst
@@ -0,0 +1,116 @@
+Quickstart Guide: Editing
+=========================
+
+Intent
+------
+
+This quickstart guide decribes how to modify and commit changes that will
+be visible on http://docs.voltha.org.
+
+Clone repo:voltha-docs
+----------------------
+
+.. code:: bash
+
+   # Clone repo:voltha-docs
+   git clone ssh://gerrit.opencord.org:29418/voltha-docs.git
+
+   # Create a developer branch
+   git checkout -b dev-joey
+
+.. code-block: shell-session
+   :linenos: 2
+
+   # Clone repo:voltha-docs
+   git clone ssh://gerrit.opencord.org:29418/voltha-docs.git
+
+   # Create a developer branch
+   git checkout -b dev-joey
+
+Repositories:
+`gerrit <https://gerrit.opencord.org/plugins/gitiles/voltha-docs>`_
+`github <https://github.com/opencord/voltha-docs>`_
+
+.. code-block: shell-session
+   :linenos: 2,5
+
+   # Clone repo:voltha-docs
+   git clone ssh://gerrit.opencord.org:29418/voltha-docs.git
+
+   # Create a developer branch
+   git checkout -b dev-joey
+
+Interactive development
+-----------------------
+
+.. code-block: shell-session
+   :caption: Launch a browser for viewing local edits
+   :linenos: 4
+
+   cd voltha-docs
+   make reload
+
+- source edit: modify reStructuredText (RST) sources
+- Modify content to taste
+
+Invoke checkin tests locally
+----------------------------
+
+.. code-block: shell-session
+   :linenos: 3
+
+   cd voltha-docs
+   make sterile
+   make test
+
+.. list-table:: makefile targets for testing
+   :widths: 30,50
+   :header-rows: 2
+
+   * - make target
+     - Description
+   * -
+     -
+   * - make test
+     - Kitchen sink target: invokes all checkin tests (make lint linkcheck)
+   * - make lint
+     - Syntax check by source: rst, python
+   * - make linkcheck
+     - Verify URLs inlined within rst files are valid
+
+Document and commit changes for ``git log``
+-------------------------------------------
+
+.. code-block: shell-session
+   :linenos:
+
+   # Commit message: Line 1 symmarize changes with jira ticket linkage.
+   echo '[VOL-XXXX] update voltha.docs' > commit_message
+
+   # Commit message: Capture list of modified files
+   git status >> commit_message
+
+   # Commit message: Capture source diffs
+   git diff >> commit_message
+
+   # Summarize changes for git log
+   $EDIT commit_message
+
+   # git add <modified files>
+
+   # Commit changes to revision control
+   git commit -F commit_message
+
+   # Rebase your sandbox, merge branch=master into branch=dev-joey
+   ... git rebase documentation URL needed here ...
+
+   # Create a patch and request a code review
+   git review --reviewers email1 email2 email3
+
+Extra credit
+-------------------------------------------
+
+.. code-block: shell-session
+
+   make sterile
+   make html 2>&1 | sed -e 's/WARNING/\nWARNING/g' | less --ignore-case --hilite-search '/WARNING'