custom map tile server supports annotation layer

src/lib/server_settings.js

@@ -53,10 +53,18 @@ export function isMapDataFetchProxyEnabled() {
     return getServerSetting('mp') === '1';
 }
 
-export function getCustomMapTileServerUrl() {
+export function getCustomMapTileLayerUrl() {
     return getServerDecodedSetting('cmsu');
 }
 
+export function getCustomMapAnnotationLayerUrl() {
+    return getServerDecodedSetting('cmau');
+}
+
+export function isCustomMapAnnotationLayerDataFetchProxyEnabled() {
+    return getServerSetting('cmap') === '1';
+}
+
 export function getCustomMapMinZoomLevel() {
     const zoomLevelSettings = (getServerSetting('cmzl') || '').split('-');
     return (zoomLevelSettings && zoomLevelSettings[0]) ? parseInt(zoomLevelSettings[0]) : 1;