feat: add 0x03_button_rust driver with 8 unit tests

drivers/0x03_button_rust/src/lib.rs

@@ -0,0 +1,8 @@
+//! @file lib.rs
+//! @brief Library root for the button driver crate
+//! @author Kevin Thomas
+//! @date 2025
+
+#![no_std]
+
+pub mod button;