layouts: scale: Add position parameter

layouts/shortcodes/leaflet-map.html

@@ -50,7 +50,9 @@ Track options:
 
 Scale options:
 
-	(none)
+	position:
+		Position of the scale. One of: "topleft", "topright", "bottomleft", "bottomright"
+		Optional, defaults to "bottomright".
 
 Elevation profile options:
 

layouts/shortcodes/leaflet-scale.html

@@ -5,5 +5,10 @@
 {{ $uniqueMapId := .Parent.Ordinal | safeJS }}
 
 <script>
-	map_options_{{ $uniqueMapId }}.scale = { enabled: true };
+	map_options_{{ $uniqueMapId }}.scale = {
+		enabled: true,
+		{{ with .Get "position" }}
+		position: {{ . }},
+		{{ end }}
+	};
 </script>