Add awbreezedark theme option to GUI

[sm-shaw]

As discussed in https://github.com/TPC-Council/HammerDB/issues/751 PR adds awbreezedark theme option to both Windows and Linux. PR restores the dark theme option lost when moving to SVG graphics, however new dark theme also now uses SVG graphics so continues to scale on UHD displays for both light and dark options (tested on Surface Book display).

For testing option can be selected by changing the scaletheme option in genericxml to awbreezedark.

<?xml version="1.0" encoding="utf-8"?>
<hammerdb>
   <theme>
        <scaling>auto</scaling>
        <scaletheme>awbreezedark</scaletheme>
        <pixelsperpoint>auto</pixelsperpoint>
   </theme>
...