move maybe-usable-by-other-cc-components to pkg. Fix all files to use the new paths (#88)

pkg/multiChanTicker/README.md

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+# MultiChanTicker
+
+The idea of this ticker is to multiply the output channels. The original Golang `time.Ticker` provides only a single output channel, so the signal can only be received by a single other class. This ticker allows to add multiple channels which get all notified about the time tick.
+
+```golang
+type MultiChanTicker interface {
+	Init(duration time.Duration)
+	AddChannel(chan time.Time)
+}
+```
+
+The MultiChanTicker is created similarly to the common `time.Ticker`:
+
+```golang
+NewTicker(duration time.Duration) MultiChanTicker
+```
+
+Afterwards, you can add channels:
+
+```golang
+t := MultiChanTicker(duration)
+c1 := make(chan time.Time)
+c2 := make(chan time.Time)
+t.AddChannel(c1)
+t.AddChannel(c2)
+
+for {
+    select {
+    case t1 := <- c1:
+        log.Print(t1)
+    case t2 := <- c2:
+        log.Print(t2)
+    }
+}
+```
+
+The result should be the same `time.Time` output in both channels, notified "simultaneously".

pkg/multiChanTicker/multiChanTicker.go

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+package multiChanTicker
+
+import (
+	"time"
+
+	cclog "github.com/ClusterCockpit/cc-metric-collector/pkg/ccLogger"
+)
+
+type multiChanTicker struct {
+	ticker   *time.Ticker
+	channels []chan time.Time
+	done     chan bool
+}
+
+type MultiChanTicker interface {
+	Init(duration time.Duration)
+	AddChannel(chan time.Time)
+	Close()
+}
+
+func (t *multiChanTicker) Init(duration time.Duration) {
+	t.ticker = time.NewTicker(duration)
+	t.done = make(chan bool)
+	go func() {
+		done := func() {
+			close(t.done)
+			cclog.ComponentDebug("MultiChanTicker", "DONE")
+		}
+		for {
+			select {
+			case <-t.done:
+				done()
+				return
+			case ts := <-t.ticker.C:
+				cclog.ComponentDebug("MultiChanTicker", "Tick", ts)
+				for _, c := range t.channels {
+					select {
+					case <-t.done:
+						done()
+						return
+					case c <- ts:
+					}
+				}
+			}
+		}
+	}()
+}
+
+func (t *multiChanTicker) AddChannel(channel chan time.Time) {
+	t.channels = append(t.channels, channel)
+}
+
+func (t *multiChanTicker) Close() {
+	cclog.ComponentDebug("MultiChanTicker", "CLOSE")
+	t.done <- true
+	// wait for close of channel t.done
+	<-t.done
+}
+
+func NewTicker(duration time.Duration) MultiChanTicker {
+	t := &multiChanTicker{}
+	t.Init(duration)
+	return t
+}