[VOL-5009] Update release notes, jira tickets.

release_notes/legend_onos_matrix.rst
release_notes/legend_voltha_matrix.rst
--------------------------------------
  o Added legend page for ONOS and VOLTHA release matrix.
  o Document column usage.

release_notes/voltha_2.12.rst
-----------------------------
  o Update more published version strings.
  o VOLTHA Column labels to be less verbose.
  o Remove column 'Component Ver' as unsued.
  o Add convenience links for column headers Go(lang) and Pypi.
  o Alphabetize VOLTHA table by component name.
    Prior sort was in hierarchy/build order, more difficult to find items.

Change-Id: I66c976a113266121de173a1483f847c9ec732016
diff --git a/release_notes/legend_onos_matrix.rst b/release_notes/legend_onos_matrix.rst
new file mode 100644
index 0000000..160528a
--- /dev/null
+++ b/release_notes/legend_onos_matrix.rst
@@ -0,0 +1,24 @@
+.. _Release Notes Legend for ONOS:
+
+# Release Matrix Legend(s)
+
+.. list-table:: ONOS Components
+   :widths: 10, 60
+   :header-rows: 1
+
+   * - Name
+     - Description
+   * - Artifact Ver
+     - Version published to Maven Central.
+   * - API Version
+     - Versioned api-{package} artifact on Maven Central
+   * - APP Version
+     - Versioned app-{package} artifact on Maven Central
+   * - Pkg Version
+     - Versioned {package} artifact on Maven Central
+   * - Gerrit URL
+     - Code repository tag for published artifact.
+   * - Github URL
+     - Code repository tag for published artifact.
+   * - Released
+     - Release WIP tracking, ``N`` signifies repository release is pending.