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-backup-client.rs

@@ -1494,6 +1494,6 @@ fn main() {
 
     let rpcenv = CliEnvironment::new();
     run_cli_command(cmd_def, rpcenv, Some(|future| {
-        proxmox_backup::tools::runtime::main(future)
+        pbs_runtime::main(future)
     }));
 }