ClientSuite: Add WorkerManager

GUIs.ClientSuite/Workers/IWorker.vb

@@ -0,0 +1,12 @@
+Imports System.Timers
+
+Namespace Workers
+    Public Interface IWorker
+        ReadOnly Property Interval As Integer
+
+        Sub Setup()
+        Sub Teardown()
+        Sub Callback(manager As WorkerManager, e As ElapsedEventArgs)
+    End Interface
+End Namespace
+