Standards compliance

[NGnius]

Rewrite interfacing to use standards like gRPC to make it easier to interoperate with other implementations. Maybe also use SSL for encryption instead of single-key RSA.

[NGnius]

Initial work for gRPC compatibility is in a new repository since it didn't make sense to couple it to USDPL.

gRPC is designed to use HTTP/2 and isn't directly compatible with browsers (though gRPC-web is, but it's not that great). With that limitation in mind, I've started work on a version of gRPC which is as close as possible to the spec, but uses websockets instead.

Next step is to port built-in web APIs to .proto files and rewrite them as a nRPC service to replace the existing data serialization functionality in usdpl-core.

[NGnius]

Initial work on USDPL nRPC framework/codegen stuff is in the next branch.