- Updated editor, and other area, styles to look okay in dark mode.
- Used tinyMCE theme generator to create dark mode theme.
- Updated tinymce to latest 4x version.
Since the old library was GPLv3 i changed the color picker to tiny-color-picker which is MIT.
Also extracted the styles to a shared view and move color calculation logic to javascript side.
This certainly should not be seen as the final implementation of this.
I imagine that requests like this will happen for many other colors in
the system, it might be good at some point to allow them to upload their
own stylesheet to be used.
