Add a get_static_info rpc for TUI API

[mkundu1]

Currently the tuigen is failing randomly during CI run with the following error:

2022-06-08 11:16:24,640 root         ERROR    GRPC_ERROR: basic_string::erase: __pos (which is 18446744073709551615) > this->size() (which is 0)

One possible issue is the huge number of API calls to get child-menu names and help-strings at each level. We can replace those with a single get_static_info rpc call similar to the datamodel and settings API.

[seanpearsonuk]

ADO 682015