[Feat] Use a job for database migration

[sleipnir]

Describe the feature
Currently, each Pod performs a complete database migration. The proposal would be to transfer this responsibility to a Kubernetes Job that could, preferably, execute before the application pods are started. This way, only one migration execution would occur instead of n times as it happens today.

Why would that be important to you?
Avoids unnecessary migration runs and reduces proxy startup time.