Use dark and light variants from seletskiy

[blueyed]

This adds the files from @seletskiy and removes the buggy solarized file.

• https://github.com/seletskiy/dotfiles/blob/25c02bf7a8d76de3152bae78a2e509dfb5f840a8/.Xresources.dark
• https://github.com/seletskiy/dotfiles/blob/6e23f28a433efced48f1ae83272cafa5f210a70a/.Xresources.light

Fixes #1, fixes #5, ref #3.
Closes #4.

[blueyed]

For reference, in my dotfiles / Xresources file I am also defining explicit resource names to allow for starting e.g. urxvt with it (urxvt -name solarizedlight).

And there are keybindings to switch between the variants.

See blueyed/dotfiles@95d2880