Don't watch secrets

[mkuratczyk]

Watching the secrets can lead to high memory usage if there's a lot of them. It seems like we don't actually rely on this, so we can turn that off completely.

Fixes #783

[Zerpet]

I think this will have the side effect that updating the Secret won't update the user credentials in RabbitMQ. I think it's a fair trade-off, because we are fixing a legitimate problem. As a workaround, folks can use time-based reconciliation.

[mkuratczyk]

I just tried that with the 1.13.0 and it didn't work anyway. What I did was:

1. deploy the userPreDefinedCreds.yaml example
2. check with rabbitmqctl authenticate_user
3. change the secret and re-apply userPreDefinedCreds.yaml
4. check again with rabbitmqctl authenticate_user - the old password works, the new one doesn't

That's in line with the comment: https://github.com/rabbitmq/messaging-topology-operator/blob/main/docs/examples/users/userPreDefinedCreds.yaml#L7

[Zerpet]

Sure, it won't work with pre-defined creds, but it should work with secrets created as part of the User creation. In any case, time-based reconciliation would be the workaround.

[mkuratczyk]

This functionality still works for me:

1. deploy docs/examples/users/user.yaml
2. rabbitmqctl authenticate_user
3. edit the user-sample-user-credentials
4. try the new password

Seems like we didn't lose anything and we gained lower memory usage and higher security. :)