OTEL Operator adds un-needed default volume for StatefulSet

[ekarlso]

If you add a collector that has mode statefulset it will have a default volume added which is not-needed for a simple deployment unless you want to actively store state on a disk.

Here is the test for the functionality in question

opentelemetry-operator/pkg/collector/volumeclaim_test.go

Line 30 in 57abb4d

func TestVolumeClaimNewDefault(t *testing.T) {

Here is the code actually adding a PVC if there are none defined by the user (causing deployments where you don't want it to get it)

opentelemetry-operator/pkg/collector/volumeclaim.go

Line 37 in 57abb4d

// Add all user specified claims or use default.

[ekarlso]

As ref disussion on #otel-operator it should not be needed for the StatefulSet according to previous discussions and doc to have a PVC attached.
#265

https://docs.google.com/document/d/1KO9mQf9owbEsxYMe1yevwEOo5S-J0AE3g3HZyY5fZMo/edit#