Feat: add auto migrations and notifications

[MarceloRobert]

NOTE: this PR has a test commit at the end so that the CI can run and we can test the migration detection. This will be removed before merging.

Changes

• Adds auto-migration running when starting the backend
• Adds notifications for when there are new migrations on staging and production deployments
  Staging compares the current commit with the previous one, while production compares the current tag with the previous release tag

Notification will be like:

New Django migrations detected in this staging deployment:
backend/kernelCI_app/migrations/0017_treelisting_new_field.py

or

No new Django migrations detected in production deployment of release/20260304.0

Closes #1764