binder_rs: Add new methods to Parcel

Add a few new methods and a trait implementation to Parcel:
* Parcel::new() and Parcel::default() which create a new empty Parcel
  by calling AParcel_create
* Parcel::append_from() and Parcel::append_all_from()
  which call AParcel_appendFrom
* Clone trait implementation using append_all_from()

Bug: 169035750
Test: atest binder_rs-internal_test
Change-Id: I89404883e9a115676523a974646d9243ac44903b