Feat/service date attributes

[RenaudBernier]

Overview

Edited the db schema to split the scheduled_at column of the services table into 3 separate columns:

• slots
• start_date
• end_date
  These were all stored together as jsonb previously

Made changes in the frontend code to correctly interpret these new columns

Testing

Added and edited services from the frontend app, checked if the date was correctly edited on both frontend and db

Checklist

• Code is neat, readable, and works
• Code is commented where appropriate and well-documented
• Commit messages follow our guidelines
• Issue number is linked
• Branch is linked
• Reviewers are assigned (one of your tech leads)

[martin0024]

lgtm, we did it together so nothing to say.