[Feature] Hardware Components Grouping

[saikishor]

This PR allows to have hardware component grouping to allow the components to propagate errors between each other. This is very helpful if the hardware components of one of the actuator of a manipulator fails, we can propagate the error to the rest of the actuators by grouping all their hardware components to one group. In this way, we could avoid continue to execute the motion

Closes #1457

[saikishor]

The failing tests are due to the Flake8 issue :)

[christophfroehlich]

LGTM, and thanks for updating the docs as well 😁

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 87.70%. Comparing base (62b32af) to head (63e4062).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1458      +/-   ##
==========================================
+ Coverage   87.65%   87.70%   +0.04%     
==========================================
  Files         102      102              
  Lines        8619     8702      +83     
  Branches      774      780       +6     
==========================================
+ Hits         7555     7632      +77     
- Misses        788      790       +2     
- Partials      276      280       +4     

Flag	Coverage Δ
unittests	87.70% <93.33%> (+0.04%)	⬆️

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

Files	Coverage Δ
..._interface/include/hardware_interface/actuator.hpp	100.00% <ø> (ø)
.../include/hardware_interface/actuator_interface.hpp	100.00% <100.00%> (ø)
...re_interface/include/hardware_interface/sensor.hpp	66.66% <ø> (ø)
...ce/include/hardware_interface/sensor_interface.hpp	100.00% <100.00%> (ø)
...re_interface/include/hardware_interface/system.hpp	100.00% <ø> (ø)
...ce/include/hardware_interface/system_interface.hpp	100.00% <100.00%> (ø)
hardware_interface/src/actuator.cpp	75.00% <100.00%> (+0.21%)	⬆️
hardware_interface/src/component_parser.cpp	92.91% <100.00%> (+0.05%)	⬆️
...e_interface/src/mock_components/generic_system.cpp	83.52% <100.00%> (+0.13%)	⬆️
hardware_interface/src/sensor.cpp	70.40% <100.00%> (+0.30%)	⬆️
... and 4 more