server: implement access log rotation with re-open via command socket

re-use the future we already have for task log rotation to trigger
it.

Move the FileLogger in ApiConfig into an Arc, so that we can actually
update it and REST using the new one.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

src/server/rest.rs

@@ -112,7 +112,7 @@ pub struct ApiService {
 }
 
 fn log_response(
-    logfile: Option<&Mutex<FileLogger>>,
+    logfile: Option<&Arc<Mutex<FileLogger>>>,
     peer: &std::net::SocketAddr,
     method: hyper::Method,
     path_query: &str,