Set reward-size on each trial

[micahwoodard]

Move reward size form task logic level to trial level. Allows to give fraction of reward for auto reward. Closes #85

At bonsai level, default reward is set to 2ul at initialization and during session, reward size is updated in calculate reward block

[micahwoodard]

@arjunsridhar12345 breaking change here. Reward size changes from task_logic.reward_size.right_valve_volume to trial_outcome.trial.reward_size.right

[micahwoodard]

@bruno-f-cruz I moved the calculating reward size to quiescent period. Moving to iti required setting it at the beginning of the session as well so made more sense to me to move into quiescent

[micahwoodard]

@bruno-f-cruz Task engine now includes pre trial select many which sets reward size for each trial