Implement attack for robot

[paulsonnentag]

4 story points

Currently we will limit the attack to static entities (towers)

attacker component

• require movable component
• add attack action
  attack if there is a entity with health in front of current entity

attack block

• add attack action to robot-api
• add attack block (move towards position if necessary then attack)
• add destroy block (calls attack repeatedly until entity is destroyed or bot is destroyed)