Implement new PoseBroadcaster controller

[RobertWilbrandt]

This PR implements a new broadcasting controller based on the PoseSensor semantic component introduced in ros-controls/ros2_control#1775.

As described in the PoseSensor PR, my primary use-case for this is the publishing of tcp poses from robot arms. This can be more accurate than calculating forward kinematics, as robot calibrations etc. can be considered by the robot. Settings on the robot side concerning tool offsets etc. can also be included by this (at least for UR and kuka RSI). The ROS 1 ur_robot_driver used to publish this transform directly from within the hardware interface, but in ROS 2 there is not yet a standard way for providing this information. A PR for the UR ROS 2 driver already exists at UniversalRobots/Universal_Robots_ROS2_Driver#1108.

This controller publishes poses directly as geometry_msgs::msg::PoseStampeds and as tf transforms (can be disabled).

[fmauch]

Looks good to me! As @RobertWilbrandt wrote, we tested this in the UR driver already.

[bmagyar]

Would you see use of this being a chainable controller at the same time?

[codecov]

Codecov Report

Attention: Patch coverage is 92.12121% with 13 lines in your changes missing coverage. Please review.

Project coverage is 80.58%. Comparing base (f96d2fc) to head (8491b06).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
pose_broadcaster/src/pose_broadcaster.cpp	84.21%	8 Missing and 4 partials ⚠️
pose_broadcaster/test/test_pose_broadcaster.hpp	93.75%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1311      +/-   ##
==========================================
+ Coverage   80.37%   80.58%   +0.21%     
==========================================
  Files         105      109       +4     
  Lines        9387     9551     +164     
  Branches      824      830       +6     
==========================================
+ Hits         7545     7697     +152     
- Misses       1570     1578       +8     
- Partials      272      276       +4     

Flag	Coverage Δ
unittests	80.58% <92.12%> (+0.21%)	⬆️

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

Files with missing lines	Coverage Δ
...se_broadcaster/test/test_load_pose_broadcaster.cpp	100.00% <100.00%> (ø)
pose_broadcaster/test/test_pose_broadcaster.cpp	100.00% <100.00%> (ø)
pose_broadcaster/test/test_pose_broadcaster.hpp	93.75% <93.75%> (ø)
pose_broadcaster/src/pose_broadcaster.cpp	84.21% <84.21%> (ø)

... and 1 file with indirect coverage changes

[RobertWilbrandt]

I don't have much experience with chaining controllers, but this sounds like a good extension. I can work on that and extend this PR.

[fmauch]

@bmagyar This should probably be backported? The semantic component has already been backported.

[christophfroehlich]

@Mergifyio backport humble iron

[mergify]

backport humble iron

✅ Backports have been created

• #1326 Implement new PoseBroadcaster controller (backport #1311) has been created for branch humble but encountered conflicts
• #1327 Implement new PoseBroadcaster controller (backport #1311) has been created for branch iron