Replicate material operator

[TheDuckCow]

Forking this feature idea from https://github.com/TheDuckCow/MCprep/issues/124, as this part was not implemented yet.

Replicate material: In the current file, copy the node layout of the actively selected material to all others across selected objects; noting that this could wipe out customized layouts appropriate for emission vs non-emission materials, if the user is not careful.

This probably would need to be selected/initiated from the material view, so it's clear that there is an association of the actively selected material.