Allow fuzzel.ini to be customized

Instead of overwriting the entire fuzzel.ini on each theme change. Theme
changes are made to fuzzel.theme which is then imported by fuzzel.ini

Rationale:
I like to use vim binds for fuzzel and there wasn't a good way to modify
fuzzel.ini without making the end-4 update process complicated.

.config/ags/scripts/templates/fuzzel/fuzzel.theme

@@ -1,8 +1,3 @@
-font=Gabarito
-terminal=foot -e
-prompt=">>  "
-layer=overlay
-
 [colors]
 background={{ $background }}ff
 text={{ $onBackground }}ff
@@ -11,11 +6,3 @@ selection-text={{ $onSurfaceVariant }}ff
 border={{ $surfaceVariant }}dd
 match={{ $primary }}ff
 selection-match={{ $primary }}ff
-
-
-[border]
-radius=17
-width=1
-
-[dmenu]
-exit-immediately-if-empty=yes