[rkpd] Refactor rkpd_client into an independent lib for reuse

This allows rkpd_client to be reused by both keystore2 and
AVF pVM remote attestation.

Test: atest keystore2_test librkpd_client.test
Bug: 241428146
Change-Id: Ibdf95c4deb2ba499daaecd170c2971cda4e80bba
diff --git a/keystore2/src/error.rs b/keystore2/src/error.rs
index ac5ba4c..b4c57fb 100644
--- a/keystore2/src/error.rs
+++ b/keystore2/src/error.rs
@@ -27,7 +27,6 @@
 //! Keystore functions should use `anyhow::Result` to return error conditions, and context should
 //! be added every time an error is forwarded.
 
-use crate::rkpd_client::Error as RkpdError;
 pub use android_hardware_security_keymint::aidl::android::hardware::security::keymint::ErrorCode::ErrorCode;
 use android_security_rkp_aidl::aidl::android::security::rkp::IGetKeyCallback::ErrorCode::ErrorCode as GetKeyErrorCode;
 pub use android_system_keystore2::aidl::android::system::keystore2::ResponseCode::ResponseCode;
@@ -35,6 +34,7 @@
     ExceptionCode, Result as BinderResult, Status as BinderStatus, StatusCode,
 };
 use keystore2_selinux as selinux;
+use rkpd_client::Error as RkpdError;
 use std::cmp::PartialEq;
 use std::ffi::CString;