Merge changes from topics "aidl-rust-null-parcelable-flags", "aidl-rust-parcelable-holder", "aidl-rust-parcelable-trait"

* changes:
  binder_rs: Implement ParcelableHolder
  binder_rs: Add null parcelable flags
  binder_rs: Add new methods to Parcel
  binder_rs: Add Parcelable trait
  binder_rs: Implement traits for Stability