Allow updating robot gravity

[AdamPettinger]

I have a UR20 mounted on another robot that can change its orientation enough to cause problems for the arm's mounting installation.

These changes expose the set_gravity URScript functionality through the Client Library, allowing a user to update the gravity vector of the robot during live operation. There is a corresponding PR on ROS2_Driver that further exposes this as a ROS service. This is obviously risky if you calculate the gravity vector incorrectly.

[urfeex]

Thank you for your contribution. Do you plan to change anything on this given that it's a draft?

Doing a quick review the implementation seems fine, only some tests and documentation would be good.

[codecov]

Codecov Report

❌ Patch coverage is 58.33333% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 42.89%. Comparing base (030e993) to head (b6fbb5b).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
src/ur/ur_driver.cpp	0.00%	10 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #415      +/-   ##
==========================================
- Coverage   43.21%   42.89%   -0.32%     
==========================================
  Files          99       99              
  Lines        8660     8682      +22     
  Branches     1179     1182       +3     
==========================================
- Hits         3742     3724      -18     
- Misses       4639     4677      +38     
- Partials      279      281       +2     

Flag	Coverage Δ
start_ursim	81.98% <ø> (-2.64%)	⬇️
ur20-latest	40.92% <58.33%> (-0.01%)	⬇️
ur5-3.14.3	40.78% <58.33%> (-0.08%)	⬇️
ur5e-10.7.0	35.97% <58.33%> (-0.09%)	⬇️
ur5e-5.9.4	40.91% <58.33%> (-0.05%)	⬇️

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[AdamPettinger]

Honestly, drafted all three of the related PRs because I haven't tested much with real hardware on Rolling (all the way with the ur_robot_driver). We have been running this on Jazzy for months, but I just rebased on Rolling in the other repo today.

I don't expect to run into troubles, and am willing to mark this ready for review if you are. I am trying to get around to testing the Rolling version on hardware by today or tomorrow.

[urfeex]

As I said, adding tests to https://github.com/UniversalRobots/Universal_Robots_Client_Library/blob/master/tests/test_script_command_interface.cpp and documentation to https://github.com/UniversalRobots/Universal_Robots_Client_Library/blob/master/doc/architecture/script_command_interface.rst would be needed to merge this.

[urfeex]

Thank you for finishing this. That looks great! Having tests in the UrDriver wrapper would be nice, but we are missing those for the other commands, as well.