Support project management

[florianm]

Feature

Support missing API endpoints:

• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/projects/creating-a-project
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/projects/updating-project-details
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/projects/deep-updating-project-and-form-details
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/projects/enabling-project-managed-encryption
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/projects/deleting-a-project
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/project-assignments/listing-all-project-assignments
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/project-assignments/listing-all-actors-assigned-some-project-role
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/project-assignments/assigning-an-actor-to-a-project-role
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/project-assignments/revoking-a-project-role-assignment-from-an-actor
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/project-assignments/seeing-all-form-assignments-within-a-project
• [ ] https://odkcentral.docs.apiary.io/#reference/project-management/project-assignments/seeing-role-specific-form-assignments-within-a-project

Add vignettes for workflows. Assign to family project-management