Add option to show only creations in Special:Contribs, API

* Add newOnly option to Special:Contributions
* Add to i18n files
* Add ucshow={new,!new,top,!top} to list=usercontribs
* Deprecated 'uctoponly' in favor of ucshow=top per Anomie.
* Add param 'newonly' to API action=feedcontributions
* Implementation: rev_parent_id=0

Bug: 42026
Change-Id: I07d597ef378d897690097804bf7c774fdadb654c
Merge "Add option to show only creations in Special:Contribs, API"