Update Sphinx

Fix font licensing

Add spelling dict tests

Remove sphinx docs which were duplicated everywhere, refer to ONF main
docs site which is more complete

Add code of conduct and link

Change-Id: I35764345f09a4dcb082a73d4a1c0c04ce889c4a3
diff --git a/release/1.6.rst b/release/1.6.rst
index b549752..519785a 100644
--- a/release/1.6.rst
+++ b/release/1.6.rst
@@ -201,11 +201,11 @@
 
 * aether-roc-umbrella: 1.4.64
 
-`SD-Core 1.0 <https://docs.sd-core.opennetworking.org/master/release/1.0.html>`_
+:doc:`SD-Core 1.0 <sdcore:release/1.0>`
 
 * sdcore-helm-chart: 0.9.17
 
-`SD-Fabric 1.0.1 <https://docs.sd-fabric.org/1.0.1/release/1.0.1.html>`_
+:doc:`SD-Fabric 1.0.1 <sdfabric:release/1.0.1>`
 
 * sdfabric: 1.0.10