Refactored the tests so that all modules are inside the application classes. Otherwise the shutdown scheme might break at some point.

- extended the trigger tests
- removed some debug output

Introduced the DeviceModule class which provides an interface to obtain VariableNetworkNodes for device registers

move the device test out of the AppModuleConnections test into its own executable and split it into a feeding and a consuming part

Split the SCALAR_ACCESSOR macro into SCALAR_OUTPUT and SCALAR_INPUT to prevent output accessors to be created in poll mode (which makes no sense). Since some tests were using this, now instead a DeviceAccessor in poll mode is used for these tests.

move the testTwoScalarPollPushAccessors into its own executable, which will contain all tests of illegal combinations

- all supported types
- check asynchronous behaviour
- check multiple consumers