Add support for provided SSLContexts in Artemis

SSL in messaging is handled by Artemis and it is enabled by a set of properties inserted into the acceptor/connector configuration. Ideally we should be able to change Artemis so that it would obtain an SSLContext that is ready to use from Elytron instead of relying on a set of properties to set up an SSLContext itself. This would help keep all SSL related configuration centralized in the Elytron subsystem and should simplify the configuration for SSL.