I've never liked how HTMLForm guesses the method names that return
each field's HTML based on the $displayFormat property, for example
`$displayFormat === 'div'` resulting in using `->getDiv()`. Recently
this mechanism resulted in CodexHTMLForm lying about its display
format to get the desired result. Instead, explicitly switch based
on the display format and call the appropriate method, and override
this in subclasses when using subclasses.
Change-Id: I91b802ac63622e3b592be589d89ea11117a616f8
Changes:
* Use Codex markup instead of mediawiki ui markup
* We limit what can be customized by the skin
* Current rules for touch area and snapping of
inputs is moved from Minerva into core so other skins
benefit from the styling
* A placeholder text is adding to the "real name" field.
* Introduce CodexHTMLForm
Bug: T182050
Change-Id: I834cc0e07fc1e705753df6866a5eeda2ac77fb8e
