ynl-gen-cpp: add support for generating rt-addr

[zb-gong]

Add support for generating rt-addr:

1. There is a duplicate space when generating ynl_cpp::ynl_socket& ys.
2. Current implementation uses reference instead of pointer as function arguments, so member access should use . instead of ->
3. operation can have empty attr_list with a fixed header. In that case, the struct should be generated as well.

The other changes are auto-formatted by vscode.