Update OpenSSL

[fridtjof]

Currently this is using OpenSSL 1.0.0l, which has been unsupported for more than 9 years.

It's also using a secondary mirror for the OpenSSL code, with manual commits of updated releases: https://github.com/mkrautz/openssl-mirror
I'm assuming the main reason was to simplify the build by not having to run a configure step through XCode?

• Determine differences between upstream 1.0.0l and said mirror

Either:

• make newer OpenSSL versions work (and possibly deal with integrating their build system into the XCode project)
• Explore replacing OpenSSL with platform APIs (as this framework is mainly intended for iOS, and maybe macOS)

[fridtjof]

Some notes:

Mostly the same state as the openssl-mirror repo can be achieved by running ./Configure dist in the openssl directory.

Not too sure how to do this with XCode's build system, but I guess it would need to run that before trying to compile anything in OpenSSL

OpenSSL is used in these places in MumbleKit:

So basically for certificate handling (I'm guessing user certificates?) and encryption (OCB-AES128) for the data [1].

[1] https://github.com/mumble-voip/mumble/blob/45899a1890808340f20e618322da6a32640c9129/docs/dev/network-protocol/overview.md#user-content-fn-2-ffb54b0de3201bb75d17369cab923146

[fridtjof]

We're now at 1.0.2u using the upstream repository.