[VOL-5061] - docs.voltha.org: Update release page.On branch dev-joey

[VOL-5079]

conf.py
sphinx_conf/exclude_patterns.py
sphinx_conf/linkcheck_ignore.py
-------------------------------
  o Refactor large URL and path exclusion lists into separate files.
  o Update linkcheck release_notes/*.html patterns to exclude by regex.

release_notes/voltha_2.12.rst
-----------------------------
  o Update deployed package grid with current version strings.
  o Re-arrange structure to display 'artifacts', include links
    for pkg, pkg-app and pkg-api artifact downloads.
  o Replace sonatype/nexus urls(staging) with direct links to maven central.

requirements.txt
----------------
  o Added missing python package sphinx-reload.

howto/release/components/apache-karaf/
howto/release/components/atomix/
howto/release/components/onos/
--------------------------------------
  o Capture dependencies, version upgrades and sources to endit
    for current package release deployments.

To view changes live:
  o git checkout voltha-docs
  o cd voltha-docs
  o make reload

Change-Id: I7b88f9d4d3329abcbe98ebbb4dbb94587088f8b9
diff --git a/sphinx_conf/exclude_patterns.py b/sphinx_conf/exclude_patterns.py
new file mode 100644
index 0000000..82bf7c7
--- /dev/null
+++ b/sphinx_conf/exclude_patterns.py
@@ -0,0 +1,45 @@
+# -*- coding: utf-8 -*-
+#
+# Configuration file for the Sphinx documentation builder.
+#
+# -----------------------------------------------------------------------
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path.
+exclude_patterns = [
+    '*/LICENSE.md',
+    '*/RELEASE_NOTES.md',
+    '*/vendor',
+    '.DS_Store',
+    'Thumbs.db',
+    '_build',
+    'voltha-go/BUILD.md',
+    'cord-tester/venv_cord',
+    'cord-tester/docs',
+    'cord-tester/src',
+    'cord-tester/README.md',
+    'cord-tester/cord-robot/README.rst',
+    'openolt/agent/*',
+    'repos',
+    'requirements.txt',
+    'bbsim/README.md',
+    'CODE_OF_CONDUCT.md',
+    '*/CODE_OF_CONDUCT.md',
+
+    # Ignore all:
+    'makefiles',
+    '__pycache__',
+    '**/__pycache__', # generated - faster traversal
+    '.venv',
+    '**/.venv',       # external virtual env
+
+    # Revisit: one directory pattern is sufficient.
+    # makefiles/virtualenv.mk normalizes all of this
+    '**/doc_venv', 
+    '**/venv_docs',
+    '**/virtualenv',
+    '**/vst_venv',
+]
+
+# [EOF]