Annotation support

Provide support for annotations in faasd with namespaced container
labels. Unit tested and confirmed with end to end test via faasd
deployed to multipass VM

Signed-off-by: Alex Tomic <atomic777@gmail.com>

pkg/provider/handlers/functions_test.go

@@ -0,0 +1,29 @@
+package handlers
+
+import (
+	"fmt"
+	"testing"
+)
+
+func Test_BuildLabelsAndAnnotationsFromServiceSpec_Annotations(t *testing.T) {
+	container := map[string]string{
+		"qwer": "ty",
+		"dvor": "ak",
+		fmt.Sprintf("%scurrent-time", annotationLabelPrefix): "5 Nov 20:10:20 PST 1955",
+		fmt.Sprintf("%sfuture-time", annotationLabelPrefix):  "21 Oct 20:10:20 PST 2015",
+	}
+
+	labels, annotation := buildLabelsAndAnnotations(container)
+
+	if len(labels) != 2 {
+		t.Errorf("want: %d labels got: %d", 2, len(labels))
+	}
+
+	if len(annotation) != 2 {
+		t.Errorf("want: %d annotation got: %d", 1, len(annotation))
+	}
+
+	if _, ok := annotation["current-time"]; !ok {
+		t.Errorf("want: '%s' entry in annotation map got: key not found", "current-time")
+	}
+}