Unify RpcModule types (#350)

* Remove register_* from Server

* Tests pass

* Some cleanup

* more cleanup

* Less bounds

* Remove the `RpcMethod` trait – I don't think we need it.

* fmt

* Fix benches

* Enable merging two modules with different contexts

* Module registration returns number of methods on the server and checks for dupes
Tests for module registration and some cleanup

* Export `RpcModule` from façade crate
fmt

* Revert to return error from `Server::register_module`

* Remove Server::methods

* Remove TODO

* Fix tests
Fix http server to work the same as ws-server

* Server::method_names

* fmt

* fix clippy warnings

Co-authored-by: Niklas Adolfsson <[email protected]>