Draft: Update Helm Chart

[swarnat]

We add some extra topics into this helm chart, because it don't exactly match our requirements

• At first we make mariadb optional, because we run a galera cluster on kubernetes and don't need an extra database pod.
• We add compatiblity to Kubernetes > 1.20, where Ingress is part of networking.k8s.io/v1
• We added php session settings to extend auto logout. This is work in progress, because we normally would also use redis session storage, which passbolt Docker image cannot use
• We add jwt keys
• At least we adjust README a little bit to give an usage example

This is marked as Draft, because we would like to make it possible to use > 1 replica for higher availablity. But this is prevented by PHP Sessions at the moment.

[claudio-walser]

Hi Stefan

Thank you for your contribution. We will check this PR as soon as possible.

Regards Claudio