Add integration tests to the CI

[allanger]

It would make sense to test that this container is actually backing databases up

TODO:

• Add a step that spins up a postgres database in the CI
• Write some data to this database
• Use local config for rclone not to run any additional storages
• Create a backup using the container
• Remove the database and run a new one
• Restore the backup
• Check the data

**AC: **

• Container is tested in CI