Core: added module to alter node label for sticky

# Ready State: Yes

https://imagex.atlassian.net/browse/LDC-161
module, renames core node-edit from sticky to pinned
updated README to add extension module

## Requirements & Dependencies

* imagex_content_pinned

## Deployment Instructions

* Merge code.

## Usage/Test Instructions

* ensure once enabled this module overrides node sticky title  as expected.