#24166 - Refactor of Shotgun Write node

Incorporates feedback, bug fixes and feature requests received over the last year, including:

#23884 - implementation of conversion methods on app to convert to/from regular Nuke Write nodes
#20697 - ability to control the Toolkit channel from the node name
#21178 - Nuke scripts are no longer left in a modified state immediately after opening
#22421 - Fixed issues with threading evaluation during rendering that could cause frames not to render
#23372 - Added support for separate proxy render & publish templates
#23373 - Added missing fields from regular Write nodes (e.g. Reading)
#23682 - Removed auto-naming functionality which was causing lots of problems
#23714 - Improved channel name handling
#23806 - Disabling node now disables the contained Write node
#23880 - Fixed issues stopping cacheing from working in Nuke 7+
#23898 - Relaxed template field requirements
#24004 - Added ability to switch between profiles without having to delete/recreate the node

Additionally, this version includes improved error messages/handling when something is wrong, copy-path button and various other minor improvements!