Fix styling of deletion page when $wgUseMediaWikiUIEverywhere enabled

* Stop using tables use divs instead. It's the future!
* Update MediaWiki UI so that inline inputs have a minimum width (as pointed
  out by Bartosz, the summary field would've gotten smaller than it was
  before to the point of being near unusable).
* Change submit button to be mw-ui-destructive (it deletes a page after all).
* Switch to using Html rather than Xml where possible.

Bug: 70134
Change-Id: Ic308a43cb0ec26ea9fdb8c9c8aa0de481a922435
Merge "Fix styling of deletion page when $wgUseMediaWikiUIEverywhere enabled"