Add missing S3 parameters

[jessebot]

Description of the change

This adds the remaining variables that are due to eventually be added in the upstream https://github.com/nextcloud/docker/pull/2271. All of these parameters are documented here.

Benefits

Now users will be able to set every single documented Nextcloud S3 parameter, even if it's not yet supported in the docker image upstream.

Possible drawbacks

Some of these env vars are not yet merged in the docker container repo, which may cause some confusion, but shouldn't make a difference overall.

Applicable issues

• fixes #612

Additional information

Checklist

• [x] I have read the CONTRIBUTING.md doc.
• [x] DCO has been signed off on the commit.
• [x] Chart version bumped in Chart.yaml according to semver.
• [x] (optional) Parameters are documented in the README.md

[jessebot]

oops, forgot to update the README. Let me do that 🤦 Edit: done.

[jessebot]

Taking a look at why the test failed now 🤔 (edit: was a typo, is now fixed)

[provokateurin]

As I said in https://github.com/nextcloud/helm/pull/613#issuecomment-2255422641 I feel it is better to let upstream confirm the changes since they know best how to do this stuff. You already mentioned the config files being out of sync can cause confusion and I'd like to avoid that.