Integrate DataStore with Payload entry

[mylibrar]

Is your feature request related to a problem? Please describe.
This is a follow-up issue to #840. After we restructure the payload system in #828, we have a new ontology called Payload and it's not entirely integrated to DataStore yet. Currently DataPack stores three payload lists for different modalities. We want to migrate them into DataStore without affecting the current interfaces.

Depends on

• Integrate DataStore with CV ontologies #840

Describe the solution you'd like

• We should maintain all payload lists in DataStore
  • __getitem__ should be efficient
• Design how Payload's attributes can be stored in DataStore as primitive and built-in types.
  • Need to determine how to handle the dataclass and non-dataclass fields.
  • Remove __getstate__ and __setstate__ from Payload
• We should keep the previous interfaces of accessing payloads, e.g., pack.text_payloads[text_payload_index]

Additional context

• This is part of the data efficiency project
• This PR should be made to the master branch.

[mylibrar]

#882 (comment)