Add possibility to add labels to HeadLess service

[Adis-J]

Feature:
We need to be able to search for the headless service with the labels but currently such a feat is impossible.

Solution:
I would like to have in the tenant resource a field in serviceMetadata for this purpose

We currently add it by hand every time but it is a big pain point

[ramondeklein]

We do provide labels for .spec.serviceMetaData.minioServiceLabels that is typically used to access MinIO (the non-headless service). Why do you need access through the headless service instead? The headless service is mostly uses for inter-node communication.

[Adis-J]

In our use case, we used the headless service because it felt the most appropriate, but if it is not the intended way we will change it. But as for the labels why did you not implement the capacity to specify the labels for this service too as you did for all the others, was there a particular reason ?

[ramondeklein]

Problem with using headless service is that it will use DNS round-robin load balancing. That's often not the preferred way to distribute the load. Unless you need extremely low-latency connections, you may want to use the headless service (it will skip the load-balancer). If you want to use this, then consider using MinIO Sidekick.

There has never been the need to label the headless service and we don't want to make the CRD even more complicated with adding options that (hardly) anyone uses.