Transclusion editing

Objectives:

* Rename just about every use of "template" to "transclusion"
* Make a proper data structure for transclusions
* Abstract away template data
* Use more template data in the user interface
* Allow adding parameters
* Allow removing templates, parameters and content

Changes:

ve.ui.Dialog.css
* Add rule to place add param controls on a single line

ve.ui.MWTemplateDialogs.js
* Move template spec loading into transclusion class
* Add remove button for parts and parameters
* Add parameter adding form
* Use template data for labels and descriptions

ve.dm.*
* Add new transclusion data structures

*.php
* Add links to new files

*.*
* Rename all things "template" to "transclusion"

Bug: 39598
Bug: 49403
Change-Id: I3bcf924a3e179cb65f19e833277a39dfd3dad8bd
Merge "Transclusion editing"