XWIKI-21988: Page naming strategy is blocking creation of pages not respecting it (#3229)

The goal here is to immediately display a feedback in the create page
dialog telling the user that the reference is wrong before they click on
create.

I performed following changes here:
  * Refactor CreateActionRequestHandler to have a clean separation
    between retrieving the reference and performing checks over
templates
  * Refactor a bit CreateAction to perform immediate checks over the
    rights and the name strategy before even checking if the template is
chosen: the goal being here to immediately provide exception if there's
a problem
  * Refactor createinline.vm to inject bootstrap modal html elements
    when used with an ajax request: the idea here is to display an ajax
modal instead of the old deprecated xwiki dialog
  * Refactor xwiki.js to use a jquery ajax call to request and display
    createinline
  * Add listener on xwiki:dom:updated events in both create.js and
    select.js to properly load them in case of dom updates
  * Provide new translations for getting better information from the
    name strategy
  * Improve a bit the template for displaying errors
  * Fix page test
  * Fix page object
  * Move translations
  * Fix typos in translations
  * Fix since

(cherry picked from commit 0d91409d)