Fix/s3 config secret

[spastorclovr]

What problem are we solving?

This PR fixes couple of issues with s3 and its config as a secret :

1. the filer statefulset would try to mount the secret even if s3 is not enabled
2. the s3 deployment tests existingConfigSecret wrongly from .Values.filer.s3
3. the secret could be created enven if s3 is not enabled or enableAuth is not on

How are we solving the problem?

1. use the secret only when Values.filer.s3.enabled is on in filer-statefulset.yaml
2. fix wrong condition to test if an existingConfigSecret is used in s3-deployment (.Values.filer.s3.existingConfigSecret vs .Values.s3.existingConfigSecret)
3. rewrite the condtion to create the secret to make sure we check for both s3 and filer.s3 if s3 is enabled and .enableAuth is on + removed the use of skipAuthSecretCreation which is redondant with existingConfigSecret

How is the PR tested?

Manually

Checks

• I have added unit tests if possible.
• I will add related wiki document changes and link to this PR after merging.

[spastorclovr]

Thx for merging @chrislusf when do you think we could have it released into the helm Chart? I understand that the helm Chart is now triggered on new tag only (which is great to avoid breaking changes) 👍