Update template for release notes and CHANGELOG with latest few summaries from ngraph releases repo (#2696)

* Update Release Notes for Github summaries, incorporate feedback from doc review, fix typos, etc

* Fix links

* Rename RCs on template

* PR reviews

* Remove trailing spaces and add clarification on Python API example

* Fix typo

* Cleaner API doc reference for compile call

* Add a useful table for nGraph namespaces

* Remove layout namespace

* Show exploding kernel problem on illustration like IEEE preso

* WIP branch for new documentation restructuring that is a huge pain

* Fix the doc reorg mess

* Fix underline

* List of passes disclaimer note

* Update disclaimers on README

* More cleanup of doc reorg

* Update core docs

* Update overview on core

* Add PR feedback

* Get rid of all the gazillion of doc build errors from rearranging stuff

* Add section on tutorials

* Update branch

* Cleanup intro

* Add better detail to overview

* Cleaner API doc reference for compile call

* Add a useful table for nGraph namespaces

* Remove layout namespace

* Show exploding kernel problem on illustration like IEEE preso

* Add new Introduction section based on IEEE presentation and illustrations

* WIP changes to doc navigation

* Update illustrations

* Cleaner ToC

* Minor fixes to the theme and removing useless bower files

* Better captions

* Revise intro

* Latest

* Make framework support section be its own section

* More updates to backend support section and add a new cpp api

* add changes to section

* Update intro with better detail

* Rework intro with better detail on motivation

* Editing

* Update README with new contrib guide filename

* Add the illustration referred to RE MobileNet group convolution fusion

* Fix off-by-a-line emph on code description

* Fix off-by-a-line emph on code description

* Re-align docs with code example for mnist

* Also fix dist_mnist and add context highlight

* [doc] Fix code snippet in derive-for-training

* Fix another code snippet in derive-for-training

Also the ONNX how to import file was tested and it was discovered
that the wheel was actually output to a different directory than
the one specified.

* WIP editing so far for review and feedback

* Add missing env var export for neon install new process

* Add modified venv setup for TF

* More edits for FW integration and landpage

* Revise from PR feedback

* More PR feedback and editing for clarity

* Minor rewording, clearer explanation

* Final pass edit

* more editing

* More extensive examples of graph building.

* Review comments

* Review comments

* Review comments