Use latest packet timestamp in GPS file, move writing into DiagTask to eliminate RwLocks, remove "sidecar" word from codebase

check/src/main.rs

@@ -155,7 +155,7 @@ async fn pcapify(qmdl_path: &PathBuf) {
         .await
         .expect("failed to get container")
     {
-        for msg in container.into_messages().into_iter().flatten() {
+        for msg in container.messages().into_iter().flatten() {
             if let Ok(Some((timestamp, parsed))) = gsmtap_parser::parse(msg) {
                 pcap_writer
                     .write_gsmtap_message(parsed, timestamp, None)