ANDROID: rust_binder: add binder_logs/state

The binderfs directory has four files intended for debugging the driver.
This patch implements the state file so that you can use it to view the
current state of the driver.

Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-18-08ba9197f637@google.com/


Change-Id: I41d33ad5149b6f5cfb2569da1db02b36f2a8b99b
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Bug: 278052745