feat: Enhance installation script and download functionality

- Add support for a force installation mode in the install script, allowing users to overwrite existing configurations and databases.
- Improve database setup logic to ensure existing users and databases are only dropped during a force installation.
- Introduce a new API endpoint to list available download files, enhancing the user experience on the download page by only displaying existing files.
- Update HTML templates to reflect the availability of download files dynamically.

server/src/api/mod.rs

@@ -59,6 +59,7 @@ pub fn router(_state: Arc<AppState>) -> Router<Arc<AppState>> {
         .route("/admin/builds/trigger", post(download::trigger_build))
         // Download
         .route("/client-config", get(download::get_client_config))
+        .route("/download/list", get(download::list_download_files))
         .route("/download/:filename", get(download::download_file))
         // WebSocket signaling
         .route("/ws", get(ws_handler))