Setup of the signal exercise

...ava/io/takima/temporalpractice/signals/ConsumeSignal.java

...io/takima/temporalpractice/signals/InventoryActivity.java

...akima/temporalpractice/signals/InventoryActivityImpl.java

...io/takima/temporalpractice/signals/InventoryWorkflow.java

src/main/java/io/takima/temporalpractice/signals/MSMain.java