When a mentee requests a session, Availability object status is updated to requested

[esparr]

Sessions update Availability status when requested

Acceptance Criteria:

• Session Request endpoint takes in one or two availability pks (30 or 60 mins)
• Status for the Availability endpoints gets updated to requested
• Includes tests for session request endpoint
• plan for production database migration and update planned

Considerations:

The sessions model will need to be updated to take more than one availability object (one to many relationship). This will need to also include some database manipulation in production. A script could be written to update this.