[browseui] Improve the TODO section situation

The TODO sections of browseui are either out of date as some of the TODOs have been fixed/implemented. Also, they are not sorted in importance at all. ex: https://svn.reactos.org/svn/reactos/trunk/reactos/dll/win32/browseui/shellbrowser.cpp?view=markup#l53
The greater importance entries are mixed in with the less important entries.

I am going to remove the outdated entries and sort them based on importance.