job: Split out from process

Rename ProcessManager to JobManager, as that's what it really handles. This
also renames get_command_object_path, which actually spawns a job instead of
just getting something. Further, it moves job spawning into the Job object
instead of being a helper function on ProcessManager.

src/lib.rs

@@ -15,6 +15,7 @@ use tracing::{info, warn};
 
 mod ds_inhibit;
 mod error;
+mod job;
 mod manager;
 mod process;
 mod sls;