CURRIKI-6056 : PROJECT: Activate Wysiwyg 2.0 instead of TinyMCE

Updated SimpleHTMLResource wysiwyg loading, parameter converInput =
false since the content is html. The contents of wysiwyg textarea now is
sent as it should, we update the asset content with slp_text now.
Default syntax for SimpleWikiResource updated to xwiki/2.1.
Displayers for TextAssetClass updated, with view included xwiki/2.1
syntax and on edit added the wysiwyg editor for both wiki syntax and
xhml/1.0
Also removed not needed .xml files from wiki module /resources