Add Minio end-user docs

[Kidswiss]

These docs explain how customers can get Minio on their clusters.

Minio is a bit a special case and usually not enabled by default, as the cloud provider's object storage is preferred by default.

Full self-service provision for Minio is unfortunately not that trivial to achieve, as each Minio instance will require a separate composition pointing to that instance and wiring up the credentials to work with the ObjectBucket objects.

So to get full self-service for Minio we'd need to engineer a composition which in turn creates new compositions on the fly. While it's doable with composition functions, it's a construct that can pretty easily explode in complexity.

Unless full self-service Minio is something our customers really crave, I'd suggest keeping it as described in the docs and put that effort in other services on the roadmap.

[tobru]

I pushed f96357f - what do you think?

[zugao]

There are some duplicates. I checked with make preview but everything seems fine, no duplicates, strange.

[zugao]

removing the duplicates and the rest just LGTM

[tobru]

removing the duplicates and the rest just LGTM

I don't understand what you mean with duplicates? Yes, some lines are duplicated because they point to the same place, in a different column.