add a global variable for cluster size factor

srcs/plugins/map_prof/scripts/mp_init_map.js

@@ -7,6 +7,7 @@ function mp_init_map() {
 	 * - let icon_cluster_url = ""
 	 * - let icon_color = ""
 	 * - let icon_size = [x, y]
+	 * - let cluster_size_factor = Number
 	 */
 
 	/*
@@ -79,8 +80,8 @@ function mp_init_map() {
 			/* CLUSTERS SETTINGS */
 
 			let cluster_icon_size = [
-				icon_size[0] + ( 2.5 * (count - 2) ),
-				icon_size[1] + ( 2.5 * (count - 2) )
+				icon_size[0] + ( cluster_size_factor * (count - 2) ),
+				icon_size[1] + ( cluster_size_factor * (count - 2) )
 			];
 			let cluster_svg = window.btoa(`
 				<svg xmlns="http://www.w3.org/2000/svg" width="${cluster_icon_size[0]}" height="${cluster_icon_size[1]}">