feat: support more langs

* add translations for French, Spanish, and Italian
* change the wording for better understanding of this feature:
    - "import" to "restore"
    - "export" to "backup"
* rename functions to reflect these changes

src/lib/WireGuard.js

@@ -319,15 +319,18 @@ Endpoint = ${WG_HOST}:${WG_CONFIG_PORT}`;
     await this.saveConfig();
   }
 
-  async uploadConfiguration(config) {
-    const _config = JSON.parse(config);
-    await this.__saveConfig(_config);
-    // force restart
+  async ___forceRestart() {
     this.__configPromise = null;
     await this.saveConfig();
   }
 
-  async downloadConfiguration() {
+  async restoreConfiguration(config) {
+    const _config = JSON.parse(config);
+    await this.__saveConfig(_config);
+    await this.___forceRestart();
+  }
+
+  async backupConfiguration() {
     const config = await this.getConfig();
     return JSON.stringify(config, null, 2);
   }