install: better install + use data and state

Don't complete remove repos, use git pull instead
Use XDG_DATA_HOME and XDG_STATE_HOME

install/shell.fish

@@ -5,10 +5,10 @@
 install-deps git dart-sass libastal-gjs-git libastal-meta npm curl libnotify ttf-material-symbols-variable-git ttf-jetbrains-mono-nerd ttf-rubik-vf pacman-contrib
 install-optional-deps 'uwsm (for systems using uwsm)' 'yay (AUR package management)' 'fd (launcher file search)' 'wl-clipboard (clipboard support)' 'foot (opening stuff in terminal)'
 
-set -l shell $CONFIG/shell
+set -l shell $C_DATA/shell
 
-confirm-overwrite $shell
-git clone 'https://github.com/caelestia-dots/shell.git' $shell
+# Update/Clone repo
+update-repo shell $shell
 
 cd $shell || exit
 npm install