implemented stdin methods for reading a string (async) and reading keystrokes (sync + async). added a very basic shell on top of it for debugging

libk/src/lib.rs

@@ -21,6 +21,7 @@ extern crate alloc;
 
 pub mod drivers;
 pub mod resources;
+pub mod util;
 
 #[allow(unused)] // We aren't using much of this right now.
 pub mod std;