split out pbs-runtime module

These are mostly tokio specific "hacks" or "workarounds" we
only really need/want in our binaries without pulling it in
via our library crates.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

src/bin/proxmox-file-restore.rs

@@ -473,6 +473,6 @@ fn main() {
     run_cli_command(
         cmd_def,
         rpcenv,
-        Some(|future| proxmox_backup::tools::runtime::main(future)),
+        Some(|future| pbs_runtime::main(future)),
     );
 }