[JTC] Make goal_time_tolerance overwrite default value only if explicitly set (backport #1192 + #1209)

[mergify]

Since #716 we process the tolerances set from the action goal. This was done as described in https://github.com/ros-controls/control_msgs/blob/65814d985aa29bed0adfaed5f2ebd8cf26266056/control_msgs/action/FollowJointTrajectory.action#L6-L10 and https://github.com/ros-controls/control_msgs/blob/65814d985aa29bed0adfaed5f2ebd8cf26266056/control_msgs/msg/JointTolerance.msg#L7-L10.

However, the goal_time_tolerance was always overwritten with the value from the action goal. This actually changed the JTC's default behavior if

• a goal_time_tolerance != 0 was set in the controller config and
• no goal_time_tolerance or explicitly a 0.0 was given in the action goal.

In this, case, the controller would wait indefinitely until the robot reached the final target independent of the goal_time_tolerance configured inside the controller's default values.

This PR makes it such as

• If a goal_time_tolerance of 0.0 is given in the action (which is the default if left empty), the value from the controller config will be used
• If a goal_time_tolerance of -1.0 is given the controller will wait at the end of the trajectory until the error gets lower than the goal_tolerance for each joint.
• If a goal_time_tolerance > 0.0 is given, the goal_time_tolerance from the action goal will be used.
• Any other negative value for goal_time_tolerance will make the controller fall back to its configured tolerances completely.

  ---

  This is an automatic backport of pull request [JTC] Make goal_time_tolerance overwrite default value only if explicitly set #1192 done by Mergify.

[codecov]

Codecov Report

Attention: Patch coverage is 95.31250% with 3 lines in your changes missing coverage. Please review.

Project coverage is 87.18%. Comparing base (f533cfd) to head (7a62ba3).

Additional details and impacted files

@@            Coverage Diff             @@
##             iron    #1207      +/-   ##
==========================================
+ Coverage   86.92%   87.18%   +0.25%     
==========================================
  Files          92       92              
  Lines        8347     8363      +16     
  Branches      699      694       -5     
==========================================
+ Hits         7256     7291      +35     
+ Misses        836      822      -14     
+ Partials      255      250       -5     

Flag	Coverage Δ
unittests	87.18% <95.31%> (+0.25%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...int_trajectory_controller/test/test_tolerances.cpp	100.00% <100.00%> (ø)
...ectory_controller/test/test_trajectory_actions.cpp	97.75% <100.00%> (ø)
...ntroller/test/test_trajectory_controller_utils.hpp	83.83% <0.00%> (-0.29%)	⬇️
...include/joint_trajectory_controller/tolerances.hpp	79.79% <94.87%> (+9.89%)	⬆️

... and 2 files with indirect coverage changes