feat: theme btop

Also change template replacement format

src/caelestia/data/templates/fuzzel.ini

@@ -28,14 +28,14 @@ radius=10
 width=2
 
 [colors]
-background=$surfacedd
-text=$onSurfacedd
-prompt=$primaryff
-placeholder=$outlineff
-input=$onSurfaceff
-match=$tertiaryff
-selection=$primary87
-selection-text=$onSurfaceff
-selection-match=$tertiaryff
-counter=$outlineff
-border=$primary77
+background={{ $surface }}dd
+text={{ $onSurface }}dd
+prompt={{ $primary }}ff
+placeholder={{ $outline }}ff
+input={{ $onSurface }}ff
+match={{ $tertiary }}ff
+selection={{ $primary }}87
+selection-text={{ $onSurface }}ff
+selection-match={{ $tertiary }}ff
+counter={{ $outline }}ff
+border={{ $primary }}77