Operator env vars documentation

currently there is hand written docs for env vars and commandline parameters, but that in itself isn't useful.

The users want to set this with Helm, or somehow in OpenShift (or maybe with stackablectl?)

These things should go into the Reference section.

We should also think about maybe generating this if we can (but not necessary, as there are probably not that many settings). Maybe we can have instead common operator flags as a partial somewhere, that we can simply reference in all the operators.

related: https://github.com/stackabletech/documentation/issues/514

首先找到现有的手写环境变量和命令行参数文档，然后查看 Reference 部分以及相关 issue 514。完成的标准是：以用户可以通过 Helm 或 OpenShift 应用的形式记录这些设置，并将有关共享 partial 或生成的任何决定记录在最终文档中。