Add rust lint CI job. (#9)

Additionally fix the many lint errors that are occurring. (or disable them).

Reviewed-on: #9
Co-authored-by: Drew Galbraith <drew@tiramisu.one>
Co-committed-by: Drew Galbraith <drew@tiramisu.one>

rust/lib/mammoth/src/thread.rs

@@ -40,7 +40,7 @@ where
     let raw_main = Box::into_raw(Box::new(main));
     let proc_cap = Capability::take_copy(unsafe { crate::init::SELF_PROC_CAP }).unwrap();
     let cap = syscall::thread_create(&proc_cap).unwrap();
-    syscall::thread_start(&cap, entry_point as u64, raw_main as u64, 0).unwrap();
+    syscall::thread_start(&cap, entry_point as usize as u64, raw_main as u64, 0).unwrap();
 
     JoinHandle { cap }
 }