[JTC] Renaming variables, reordering trajectory checks

[destogl]

This PR increseas readability of the JTC by renaming trajectory varialbes to be semantically correct and self explainable.

Also it reoders checks of the trajectories done in the callback. They are grouped based on the things they are checking, i.e., 1. data available, 2. time checks; 3. trajectory point checks.

Additionally, it adds "last_commanded_time_" for the open loop mode to be more correct when setting point before trajectory. #780

[mergify]

This pull request is in conflict. Could you fix it @destogl?

[bmagyar]

Recently merged the wraparound feature which caused some conflicts.

Also, this may be interesting for @fmauch

[christophfroehlich]

LGTM and improves readability!

[christophfroehlich]

👀 @destogl test_no_jump_when_state_tracking_error_not_updated fails now, I guess due to the last_commanded_time_ change.

[saikishor]

LGTM, apart from the following minor comment.

Now with the changes, it looks clear and good

[saikishor]

In this case, the last_command_time_ would be same for the first 2 iterations. Is that okay?. If its fine, then all good.

[bmagyar]

Please adjust / extend the tests

[christophfroehlich]

This includes #780, which has the same failing test: test_no_jump_when_state_tracking_error_not_updated

[mergify]

This pull request is in conflict. Could you fix it @destogl?

[codecov]

Codecov Report

Attention: Patch coverage is 87.17949% with 5 lines in your changes missing coverage. Please review.

Project coverage is 84.72%. Comparing base (fc20a27) to head (a2c6189).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...ory_controller/src/joint_trajectory_controller.cpp	86.84%	2 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1032      +/-   ##
==========================================
- Coverage   84.73%   84.72%   -0.01%     
==========================================
  Files         124      124              
  Lines       11408    11408              
  Branches      955      956       +1     
==========================================
- Hits         9666     9665       -1     
  Misses       1436     1436              
- Partials      306      307       +1     

Flag	Coverage Δ
unittests	84.72% <87.17%> (-0.01%)	⬇️

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

Files with missing lines	Coverage Δ
...jectory_controller/joint_trajectory_controller.hpp	100.00% <ø> (ø)
...ntroller/test/test_trajectory_controller_utils.hpp	83.92% <100.00%> (ø)
...ory_controller/src/joint_trajectory_controller.cpp	85.11% <86.84%> (-0.03%)	⬇️

... and 3 files with indirect coverage changes