Add more default color themes
I think we should provide more default color themes.
There are several well accepted and MIT licensed themes out in the wild.
e.g.
- MIT Dracula, dark theme
https://github.com/dracula/kate
=> added now, see !58 (merged) & https://kate-editor.org/themes/
- MIT ayu dark, mirage and light
Seems like a good junior job/... to provide .theme files for these.
(and hunt down some more)
Soon KTextEditor will take these all up per default and allow people to just use them in Kate/KWrite/KDevelop/Kile/... without extra effort.
A good idea would be some generated web site to demonstrate the themes one one example file. Like the light/dark refs for the highlighting auto tests this could be one auto-test, to ensure all themes are usable.