[Exe Thumbnailer] Match 16 bit executables and don't request icon types wrestool cannot handle
16 bit executables don't have --language in their output.
While at it, port to QRegularExpression and just do a global match rather than splitting the output into individual lines.
Since the name is captured very fuzzy (it can include spaces, too),
I couldn't just do an optional match but had to do two specific matches for with and without --language.
Also, somewhat fix the individual icon selection which looks broken but doesn't appear to be used anyway.
Moreover, only extract icon groups (type 14). I checked wrestool source code and it cannot actually
decode single icons (type 3) nor cursors (type 1). Calling it with --raw usually creates .dib files
which don't appear to be proper bitmaps and fail to generate thumbnails.
Differential Revision: https://phabricator.kde.org/D23145