Merge OpenSSL backend into glib-networking
The OpenSSL backend can be found here: https://gitlab.gnome.org/GNOME/glib-openssl
By merging it with glib-networking, it would be easier to discover and the code duplication between the two could be reduced (the base classes at least).
The OpenSSL backend is feature complete from what I know except for the missing DTLS support. OpenSSL supports DTLS though, so that should be possible to add at a later time and I wouldn't block on this here.
The OpenSSL backend has the following potential advantages over the GnuTLS one (apart from increasing crypto-diversity):
- It's simply faster
- Already part of some platform/application and shipping two TLS stacks is kind of suboptimal
- Companies often prefer the OpenSSL license over the whole trail of licenses GnuTLS brings with it (including the LGPLv3/GPLv2 gmp library)
- FIPS certification
- Potentially safer because of its wider usage