Move composer location to install libraries into our libraries folder

I think this is so so so much better keeping our Joomla libraries convention of being in /libraries than having stuff split between libraries and composer's vendor - which is going to just start making debugging that much harder

Now the only slightly irritating thing about this method is that we are merging the framework and /joomla code together in the libraries/joomla directory. However if we're moving around directories anyhow then we can start moving stuff out of libraries/joomla and into libraries/cms or libraries/legacy anyhow

Note the only two necessary changes are libraries/cms.php for the autoloader include + build file paths to files to ignore. The other stuff is a result of running ```composer update```.