Editing conflict handling with Notification, Merge and create Copy options

[vidhyasagargm]

Currently, only one user can edit a wiki article. If more than one user edit at the same time, they will only know after one user has saved and the other also tries to save it, as the module throws a "do you really want to overwrite changes" error. This can easily lead to data loss, either as one user is overwriting the changes or potentially losing their own changes if they decide not to overwrite - and the "back" button does not bring them back to their own changed version.

So for better user experience and usability, I created 3 different features:

1. Notification of conflict edit before entering edit
2. Create Copy of edit
3. Soft merge of edit

An internal code review process has already been done upfornt for all the changes in this PR and Issue

Here is some screenshots: