Enable remote launcher catalog source

app/assets/js/configmanager.js

@@ -476,7 +476,11 @@ exports.getLibraryCatalogSource = function(){
  * @param {string|null} source A remote URL or local path.
  */
 exports.setLibraryCatalogSource = function(source){
-    config.library.catalogSource = source
+    if(typeof source !== 'string' || source.trim().length === 0){
+        config.library.catalogSource = null
+    } else {
+        config.library.catalogSource = source.trim()
+    }
 }
 
 /**
@@ -998,3 +1002,22 @@ exports.getAllowPrerelease = function(def = false){
 exports.setAllowPrerelease = function(allowPrerelease){
     config.settings.launcher.allowPrerelease = allowPrerelease
 }
+
+/**
+ * Validate a library catalog source.
+ *
+ * @param {string} source A remote URL or local path.
+ * @returns {boolean} Whether the value is allowed.
+ */
+exports.validateLibraryCatalogSource = function(source){
+    const trimmedSource = typeof source === 'string' ? source.trim() : ''
+    if(trimmedSource.length === 0){
+        return true
+    }
+
+    if(trimmedSource.includes('://')){
+        return /^https?:\/\/\S+$/i.test(trimmedSource) || trimmedSource.startsWith('file://')
+    }
+
+    return true
+}