libressl: new package

Libressl is a fork of openssl from OpenSSL in 2014.  Its goal is to
modernize the OpenSSL codebase, improve security, and apply best
practice development processes.

Right now, libressl is API compatible with OpenSSL 1.0.1, but does not
yet include all new APIs from OpenSSL 1.0.2 and later.

Signed-off-by: Adam Duskett <aduskett@codeblue.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>