Add more flexibility in terms of weed args passed to SeaweedFS components via Operator

[faurik]

Currently, there is no way to pass arguments to weed command for master/volume/filer except predefined fields in CRD like volumeSizeLimitMB. Because of that there is no way to fine tune SeaweedFS components deployed via Operator (like change/disable concurrent download/upload limits for volume servers).

It would be great to have separate field in CRD for each component, something like extraArgs, to pass any argument we want to weed command.

Moreover, probably it would be better to refine structure of volume-related part of CRD in order to support different DCs and racks (for instance, following ScyllaDB Operator way), but this way there won't be backward compatibility.

I would like to discuss the topic first, and if it is interesting for community, I'd like also bring PR with implementation we'll choose as a result of discussion.

For reference: seaweedfs/seaweedfs#5271 (comment)

[chrislusf]

Welcome to any suggestions/PRs! This operator needs more improvements.