src: all wraps now use actual FunctionTemplate

Instead of simply creating a new v8::Object to contain the connection
information, instantiate a new instance of a FunctionTemplate. This will
allow future improvements for debugging and performance probes.

Additionally, the "provider" argument in the ReqWrap constructor is no
longer optional.

PR-URL: https://github.com/joyent/node/pull/8110


Signed-off-by: Trevor Norris <trev.norris@gmail.com>
Reviewed-by: Fedor Indutny <fedor@indutny.com>
Reviewed-by: Alexis Campailla <alexis@janeasystems.com>
Reviewed-by: Julien Gilli <julien.gilli@joyent.com>