neon_local timeline import: create timelines on safekeepers (#12138)

neon_local's timeline import subcommand creates timelines manually, but
doesn't create them on the safekeepers. If a test then tries to open an
endpoint to read from the timeline, it will error in the new world with
`--timelines-onto-safekeepers`.

Therefore, if that flag is enabled, create the timelines on the
safekeepers.

Note that this import functionality is different from the fast import
feature (https://github.com/neondatabase/neon/issues/10188, #11801).

Part of #11670
As well as part of #11712

libs/safekeeper_api/src/models.rs

@@ -13,7 +13,7 @@ use utils::pageserver_feedback::PageserverFeedback;
 use crate::membership::Configuration;
 use crate::{ServerInfo, Term};
 
-#[derive(Debug, Serialize)]
+#[derive(Debug, Serialize, Deserialize)]
 pub struct SafekeeperStatus {
     pub id: NodeId,
 }