Health check and initialization tasks

Sometimes applications need some initialization checks and updates, like:

1. Database migration
1. Create queue topic if does not exist
1. ...

At the moment the only way to achieve this kind of behaviour is implementing that in the application server.
That's not the right place if we consider that pod replicas may go in parallel trying to achieve the same goal.

A nice implementation is to have the possibility to create a ephemeral pod/job as part of the deployment that performs the desired initialization checks and tasks.

The issue names no files, tests, or entry points. Start by locating the deployment configuration and determine how an ephemeral pod or job could run database migrations, queue-topic creation, and other initialization tasks without application replicas repeating them. Done means the deployment can configure and execute these tasks separately from the application server.

Written by the indexing model from the issue text.