Docs: DOI: Extended clarification on DOI DSpace item states

[bram-atmire]

Describe the bug

The different states for DOI in an item are described here:
https://wiki.lyrasis.org/display/DSDOC7x/DOI+Digital+Object+Identifier?focusedCommentId=328958128#DOIDigitalObjectIdentifier-'cron'jobforasynchronousreservation/registration

I'm not 100% convinced this is complete & it seems to also miss the corresponding states of the DOI in DataCite itself.
I wrote up a suggestion to extend the docs:
https://wiki.lyrasis.org/display/DSDOC7x/DOI+Digital+Object+Identifier?focusedCommentId=328958128#comment-328958128

Would be great if @tdonohue or @pnbecker could review this & if good/complete, include it on the page.

[tdonohue]

@bram-atmire : I'm not the best one to review the documentation, as I'm not familiar enough with the DOI code myself.

Once @pnbecker or @kshepherd have a chance (I know DSpace Praxistreffen is going on now though), they might be the best to review it. Otherwise, I'd recommend making the changes to the docs that you feel is correct and someone else will always update it later if they find corrections to make.