RustCrypto in TockEnv (#625)

* Adds a rust_crypto feature to Tock

* -O3 for RustCrypto

deploy.py

@@ -1091,6 +1091,13 @@ if __name__ == "__main__":
       help=("Compiles the OpenSK application without backward compatible "
             "support for U2F/CTAP1 protocol."),
   )
+  main_parser.add_argument(
+      "--rust-crypto",
+      action="append_const",
+      const="rust_crypto",
+      dest="features",
+      help=("Compiles the OpenSK application with RustCrypto implementations."),
+  )
   main_parser.add_argument(
       "--nfc",
       action="append_const",