Will switch colors for running qutebrowser instance.
Will add `colorscheme.py` into default qutebrowser config directory and
make sure the file is sourced from default qutebrowser config file
`config.py`. This makes the theme change permanent.
Will theme vim on-the-fly when it is running within tmux.
When permanently setting a theme, will add a
colorscheme.vim file into the vim config directory (or nvim) for which a
source statement is added to vimrc/init.vim.
