NewLOOPPService returns a new [*PluginService].

PluginServiceName is the name for [types.PluginClient]/[NewGRPCService].

GRPCService is the loopp interface for a plugin that can run an arbitrary product in the core node.

LOOPPService is a [types.Service] that maintains an internal [types.PluginClient].

These implement `ConnToProvider` and return the conn wrapped as the specified provider type.