Introduce jquery formvalidator for com_languages

#### Executive summary

This PR converts the form validation on com_languages to use plain jquery (no mootools call on every form).
Also NO MORE INLINE SCRIPTS!

#### Testing

1. Apply first PR #4888 (!important)
2. Apply this PR
3. In the admin area go to com_languages and try to submit any form.

If no javascript errors are logged in your browser and the functionality remains the same your test is a pass in any other case please report the errors here

Please also check these:
administrator/index.php?option=com_checkin should demonstrate multiselect without mt
administrator/index.php?option=com_users&view=mail should demonstrate form sent and validate without mt
administrator/index.php?option=com_modules should demonstrate multiselect and combobox without mt
http://localhost/administrator/index.php?option=com_admin&view=sysinfo should demonstrate highlighter.js without mt
Logout and log in to demonstrate the use of noframes without mt.
@fedik you are right is not needed, but waiting for the DOM to become ready ensures that scripts will not block the DOM, which is described as best practice (is there a chance to call the function before the DOM is completed?) and will be nice if devs follow it.
Also a good reference for javascript code styling is this [post] (https://groups.google.com/forum/#!topic/joomla-dev-cms/psqdwNrXoss) in CMS Group
Of course somebody has to update the coding styles