MINOR: ssl: Added cert_key_and_chain struct

Added cert_key_and_chain struct to ssl. This struct will store the
contents of a crt path (from the config file) into memory. This will
allow us to use the data stored in memory instead of reading the file
multiple times.

This will be used to support a later commit to load multiple pkeys/certs
into a single SSL_CTX
1 file changed