[Issue]: Make coordinator availability table and backend actions

[RenaudBernier]

Branch Name

feature/119-coordinator-availability-backend

Task

• Add a new coordinatorAvailability schema in schema.ts
• Create API routes that allow the concerned coach and any admin to edit the coaches availability

A coordinator has availability slots. Each slot is at a certain time at a certain day for a certain duration.

Acceptance Criteria

• From the backend APIs, an authenticated coordinator can edit their own availability slots only
• From the backend APIs, an authenticated admin can edit any coordinator's availability slots
• Any other user can't edit coordinator availability slots

Checklist

• I have checked for duplicate issues.
• I have assigned the issue to the correct project board.
• I have tagged the issue properly.

Code of Conduct

• I agree to follow this project's Code of Conduct