Re-implement and publish to docs site as demos pertinent workflows/post-processing from the abnormal grain growth work

[Scottan]

Re-implement (and publish to docs site as demos, with suggested resource requirements) pertinent workflows/post-processing from the abnormal grain growth work:

• "grain growth reversal" simulations in 2D and 3D:
• sampling two textures from MTEX, and generating with Dream3D a volume element with a nucleus and these textures
• interface binning
• ability to change grain size
• with/without nucleus
• Processing results to allow plots of nucleus vs matrix growth curves (maybe as a new task)

[Scottan]

May be partially completed by #430