[Umbrella Feature]: Upgrade validation methods

[rly]

What would you like to see added to PyNWB?

Breaking changes (release in PyNWB 3.0)

• [Feature]: Change pynwb.validate(io=...) to match pynwb.validate(paths=[path]) #1807
• Account for all loaded namespaces during validation hdmf-dev/hdmf#608 and related Validating links across extensions can fail hdmf-dev/hdmf#525
• Move pynwb.validate into module pynwb.validation and other organizational changes Improve package modularity #1493

Non-breaking changes that would be good to do in this breaking change:

• [Feature]: entry point for validate #1756
• validator should be able to output machine readable results #1179
• Validator should throw warning if there are extra fields #942

There are a number of other validation-related issues and feature enhancements that we could tackle if time permits:
https://github.com/hdmf-dev/hdmf/issues?q=is%3Aopen+label%3A%22topic%3A+validator%22+sort%3Aupdated-desc
https://github.com/NeurodataWithoutBorders/pynwb/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+label%3A%22topic%3A+validator%22

Please suggest other features to bundle into this development.

Is your feature request related to a problem?

No response

What solution would you like?

n/a

Do you have any interest in helping implement the feature?

Yes.

Code of Conduct

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

[rly]

Also related @stephprince #1009 or clear all loaded namespaces or something.

[rly]

Also related with namespaces https://docs.google.com/document/d/1DB1dg6PEDW40Iafj-kX-y_OZJsqyne7Edah82n17zoo/edit#heading=h.k9x5xabqgniy