Update the test to support license protocol 2.2

- Add a flag ENABLE_LICENSE_PROTOCOL_2_2, when the flag is enabled
  - Hash the license request in WB_License_ProcessLicenseResponse, i.e.
    the request used for the key derivation, which ensures the key
    derivation message to be a string of constant size 64 bytes.
  - Hash the license request in WB_License_SignLicenseRequest. Note that
    the function takes license request (or hashed) + odk message as
    parameter for odk v17 or above.
- Enable the flag just for Chrome and ChromeOS for now.

We may change the implementation to hash inside the white-box in the
future.

Also included a few other misc changes, e.g. updating the DEPS of
boringssl and googletest which are already in the white-box directory,
adding a test main etc.

whitebox-impl/.bazelrc

@@ -0,0 +1 @@
+build --cxxopt='-std=c++14'