Improve binaries volume config

[matskiv]

What issue type does this pull request address? (keep at least one, remove the others)
/kind enhancement

What does this pull request do? Which issues does it resolve? (use resolves #<issue_number> if possible)
There are cases where an emptyDir volume of sufficient size can not be provided, so users should be allowed to override the /binaries volume with an alternative.
Additionally, current ephemeral storage requests are no sufficient for some distros:

k0s
# du -h /binaries/*
203.2M	/binaries/k0s

k8s
# du -h /binaries/*
108.3M	/binaries/kube-apiserver
100.9M	/binaries/kube-controller-manager
69.4M	/binaries/vcluster

eks
# du -h /binaries/*
105.8M	/binaries/kube-apiserver
98.4M	/binaries/kube-controller-manager
69.4M	/binaries/vcluster

Please provide a short message that should be published in the vcluster release notes
Fixed an issue where vcluster would request too little ephemeral storage.
Added .syncer.storage.binariesVolume helm chart value to allow overriding /binaries volume.

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[facchettos]

What is the scenario which would prevent us from using emptyDir ? I think we should hold off on adding more options if we are not sure they'd be useful

[matskiv]

What is the scenario which would prevent us from using emptyDir ? I think we should hold off on adding more options if we are not sure they'd be useful

Some clusters have strict limits for the emptyDir size, and in such cases a different type of volume will have to be used.

As for the failing test, I'll figure it out tomorrow. But after a quick check - seems I need to update structs in the loft-sh/vcluster-values, but this is not documented as far as I can see(nothing in the CONTRIBUTING.md or the test case code).