Keystore libselinux rust bindings.

Provide safe wrappers around the libselinux API needed for keystore.
 * getcon
 * selinux_check_acces
 * selabel_lookup

Test: keystore2_selinux_test
Test: keystore2_selinux_rust_bindings_host_test
Bug: 159466840
Change-Id: I73b4aa2e1da9b477965b10927eba069e6346ce6e
5 files changed