* the simplified layout omits the Nerdfonts characters that are not
found in every Fontset
* add an optional config option to opt into the simplified ui
`simplified_ui: bool`
* add a config flag that allows opting into the simplified ui
`zellij options --simplified-ui`
* move the `clean` flag to the `setup` subcommand
Corrections according to the discussion of the pull request, namely separating this idea out into a new yaml entirely called tmux-overview., and creating a tmux.yaml with just the new tmux bindings.
