Reorganize configuration of the http server building
rework the configuration used by make_app() so that one can start the
http server usig an existing grpc server by a setting the configuration
This make the make_app() function only accept one config structure
(dict), which structure would be:
graph: cls: local grpc_server: # config for spawn_java_grpc_server() ... http_rpc_server: # config for GraphServerApp() ...
graph: cls: remote url: # host:port of the running grpc server ... http_rpc_server: # config for GraphServerApp() ...
This also comes wit a few other refactorings:
- rename swh/graph/rpc/ as swh/graph/grpc/ to prevent confusion with the (http) rpc server.
- similarly, rename swh/graph/rpc_server.py as swh/graph/grpc_server.py
- and rename swh/graph/http_server.py as swh/graph/http_rpc_server.py
- remove the "graph" config section from the grpc_server config structure (it had only the "path" config entry).