Add initial config file for swappy

Change default save directory to ~/Pictures/Screenshots, otherwise
kept as default for now

system/default.nix

@@ -235,6 +235,7 @@
       ++ (with pkgs; [
         lmodern # LaTeX
         noto-fonts-emoji # Emoji
+        font-awesome # Swappy Icons
         (nerdfonts.override { fonts = [ "NerdFontsSymbolsOnly" ]; })
       ]);
     fontconfig = {

system/home/sway/default.nix

@@ -259,4 +259,5 @@
       titlebar_separator enable
     '';
   };
+  xdg.configFile."swappy/config".source = ./swappy.conf;
 }

system/home/sway/swappy.conf

@@ -0,0 +1,10 @@
+[Default]
+save_dir=$HOME/Pictures/Screenshots/
+save_filename_format=swappy-%Y%m%d-%H%M%S.png
+show_panel=false
+line_size=5
+text_size=20
+text_font=sans-serif
+paint_mode=brush
+early_exit=false
+fill_shape=false