python: Refactor build of dictionary entries for py_read_resource
    
    Use Py_BuildValue("{...}",...) for creating dictionary information
    for resource.
    
    Using helper to determine the build value format:
     - Py2: Handle lockspace and resource name as PyString with "s" format.
     - Py3: Handle lockspace and resource name as PyBytes with "y" format.
    
    Current status:
    - Py2: will build and pass tests.
    - Py3: build will fail for missing respective API calls.