Implement key_parameter in Rust.

This contains the basic functionality of key parameter.

Bug: 157664923
Test: atest --host keystore2_tests
Change-Id: I6eb325f6403c976c48c98394ad2aad625f59d2a1
diff --git a/keystore2/src/lib.rs b/keystore2/src/lib.rs
index b37773a..13ef87d 100644
--- a/keystore2/src/lib.rs
+++ b/keystore2/src/lib.rs
@@ -16,4 +16,8 @@
 
 pub mod database;
 pub mod error;
+/// Internal Representation of Key Parameter and convenience functions.
+pub mod key_parameter;
+/// Internal interface for the code to-be-generated from the keymint AIDL
+pub mod keymint_definitions;
 pub mod permission;