fix: Entity broker in entity conditions

Closes #50 (closed)

When using an EntityCondition in the StopTrigger of the Storyboard like done in this PR, the OSC engine throws an exception:

C++ exception with description "Requested key [EntityBroker] is not accessible in blackboard." thrown in the test body.

This MR introduces the following changes:

• make entity broker optional in entity condition (if it is not part of a maneuver but part of the storyboard stop trigger)
• adjust generator accordingly
• remove unused variable warning in TtcConditionTest and LongitudinalDistanceActionTest
• fix build for ActivateControllerActionTest / utils_tests

Signed-off-by: Andreas Rauschert andreas.rb.rauschert@bmw.de