net/cpp-pcp-client: New port

cpp-pcp-client is a C++ client library for the Puppet Communications Protocol
(PCP) protocol. It includes a collection of abstractions which can be used to
initiate connections to a PCP broker, wrapping the PCP message format and
performing schema validation for message bodies.

WWW: https://github.com/puppetlabs/cpp-pcp-client

With hat:	puppet