Initial implementation of simple data consent api.

[dsubak]

What are the relevant tickets?

https://github.com/mitodl/hq/issues/13277

Description (What does it do?)

Adds the simplest possible API for tracking user data sharing consent on a per-contract basis. It is simply an API which takes a consent value for a given contract and records that for the authenticated user. We may need more complicated logic at some point, but that remains to be seen at present.

How can this be tested?

• Authenticate as a user who is in a contract.
• Visit http://mitxonline.odl.local:9080/api/schema/swagger-ui/#/b2b/b2b_data_consent_create, specify the ID of the contract and a value for the "consented" parameter:
• Observe that the b2b_userb2bcontract record in the database should now have a value populated for consented_to_data_sharing and consent_modified_at corresponding to your input.

[github-actions]

OpenAPI Changes

Show/hide changes

## Changes for v0.yaml:
1 changes: 0 error, 0 warning, 1 info
info	[endpoint-added] at head/openapi/specs/v0.yaml
	in API POST /api/v0/b2b/data_consent/{contract_id}/
		endpoint added



## Changes for v1.yaml:
1 changes: 0 error, 0 warning, 1 info
info	[endpoint-added] at head/openapi/specs/v1.yaml
	in API POST /api/v0/b2b/data_consent/{contract_id}/
		endpoint added



## Changes for v2.yaml:
1 changes: 0 error, 0 warning, 1 info
info	[endpoint-added] at head/openapi/specs/v2.yaml
	in API POST /api/v0/b2b/data_consent/{contract_id}/
		endpoint added

Unexpected changes? Ensure your branch is up-to-date with main (consider rebasing).