Oak-Jackrabbit documentation for Conflict Detection and Handling

Documentation for Conflict Detection and Handling needs to be updated on [0]. Also information like if commit is of bulk type meaning commit root way, then node created and its parent node both will have commit_root property with commit revision while other grand parents onward the revision will be updated in _lastRev property only, needs to be updated.

[0] : https://jackrabbit.apache.org/oak/docs/nodestore/documentmk.html#Conflict_Detection_and_Handling