add network involvement, activity level, involvement level to support TNO data migration

[Taniya-Das]

Change(s)

Change Type:
Added

Change Category:
Interface

Changelog Entry:

1. Added organisational_network model and network_membership table, thereby adding has_membership_in field in organisation.
2. Added involvement_level and involved_in_area fields in organisation.
3. Added activity_type taxonomy and has_activity_type field in organisation.
4. Added V2 backwards compatibility function in organisation.

Will raise a separate PR to use a better serialiser to output the field_name instead of identifier in has_membership_in and involved_in_area fields.

How to Test

Covered in pytest.
To test locally, please do the database migration.

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained.
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained.
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it (but consider if this should not be a code comment or in the documentation instead).
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.
• The PR title matches the changelog entry's one-line description.

Related Issues

[joaquinvanschoren]

@mardalla could you please look into merging this PR? There is one test failing but this one seems unrelated?