Refactor collectors

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

pkg/collector/logon/logon_test.go

@@ -0,0 +1,13 @@
+package logon_test
+
+import (
+	"testing"
+
+	"github.com/prometheus-community/windows_exporter/pkg/collector/logon"
+	"github.com/prometheus-community/windows_exporter/pkg/testutils"
+)
+
+func BenchmarkCollector(b *testing.B) {
+	// No context name required as collector source is WMI
+	testutils.FuncBenchmarkCollector(b, logon.Name, logon.NewWithFlags)
+}