[imp] New Joomla update server naming. Fixes #3681

According to our new Development strategy:
http://developer.joomla.org/news/586-joomla-development-strategy.html#version_numbering

restore old values and mark it deprecated for 4.0

Update inline comments

Update config.xml

Next --> New thanks @brianteeman

Fix typos thanks @nicksavov

Fix typos thanks @nicksavov

@deprecated tag

New --> Latest @nicksavov

New --> Latest @nicksavov

Update default.php

Update en-GB.com_joomlaupdate.ini