By moving `Certificate` to `LibCrypto` it is possible to reuse a bunch
of code from in `LibCrypto` itself. It also moves some constants
and pieces of code to a more appropriate place than `LibTLS`.
This also makes future work on WebCryptoAPI easier.
This library isn't used by anything but the Android build which
currently doesn't work. We most likely won't be using a homegrown
implementation for archive formats in the future, regardless.
