[Feature]: Importing pynwb creates redundant type maps

[rly]

What would you like to see added to PyNWB?

During import of pynwb, 5 different type maps are created, and the same pynwb class is registered 3 times and the same hdmf class is registered 5 times. This seems unnecessary and because, copying type maps is slow, I think this is a major contributor to the slow import. Related to #1487.

Is your feature request related to a problem?

No response

What solution would you like?

Remove redundant creation of type maps

Do you have any interest in helping implement the feature?

Yes.

Code of Conduct

• [x] I agree to follow this project's Code of Conduct
• [x] Have you checked the Contributing document?
• [x] Have you ensured this change was not already requested?

[rly]

Also should investigate whether deepcopying the global typemap in get_type_map is necessary.