Add support for OpenSSL 1.1.0 or later

[akien-mga]

Operating system or device - Godot version:
All, but mainly Linux/*BSD - master.

Issue description:
Godot currently can't build against OpenSSL 1.1.0, only against OpenSSL 1.0.x (we ship 1.0.2h in thirdparty/openssl).

modules/openssl/stream_peer_openssl.cpp should be updated to build against the new API. Ideally, it should be able to build against both 1.0.x and 1.1.0, we might be able to use conditional version checks to use the proper API. Eventually, the bundled source should also be updated so that we can continue benefiting from upstream security fixes.

Workaround:
For the time being we should probably default to using the bundled openssl code on X11 (builtin_openssl=yes). Most people providing unofficial binaries don't pay attention to this, and users of distros defaulting to OpenSSL 1.1.0 can't run those binaries without installing a compat package, when provided.

[TierraDelFuego]

Haven't tested this (I just got 3.0 built) but the problem now might additionally be that this old openssl client will not be able to talk to upgraded servers. More and more are disabling insecure ssl and all going to TLS.

[akien-mga]

OpenSSL 1.0.x is still supported, so I don't see why it would stop working.

Edit: Don't mind the mentions of deleted comments below, those were off topic and were removed to preserve readability of this issue.