Add all sub public.text

[utkarshgupta137]

Many of the text files (like .js, .py, .sh) don't get a ql preview if any package associates with it but doesn't provide a ql plugin (ex. atom). So I've written a script which extracts all the UTIs which conform to public.text & public.unix-executable (with a few exceptions). I've added all of them to the supported UTIs. This will effectively break qlhighlight for users who also use qlstephen, so the users will have to choose one of the two.

[utkarshgupta137]

@tsdorsey @whomwah