* UX: Render wizard previews for high-DPI displays
Sets up a canvas element of twice the required dimensions, scales all coordinates by 2x, then shrinks the display in css.
* Use window.devicePixelRatio to determine scale factor
With our recent move to SVG icons, the font file does not work in the wizard. I've opted for path2D, which accepts an SVG path
Path2D is not supported by IE11 but the chances of admins running the wizard on IE11 are practically none.
https://caniuse.com/#feat=path2d
It was a dropdown to provide choices of color schemes,
and only one scheme could be shown.
With this commit, multiple color scheme previews can be displayed on
one page at the same time, making admins choose color schemes more
easily.
Theme preview windows are shrinked.
Imported default color schemes.
Co-Authored-By: Misaka 0x4e21 <misaka4e21@gmail.com>
