Fix bug in rate_limiter filter and add more tests

[christophfroehlich]

I ran in the same issue as was solved with diff_drive_controller already ros-controls/ros2_controllers#252
I added some tests, and furthermore improved the generate_parameter_library parameter declaration file.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 97.61905% with 1 line in your changes missing coverage. Please review.

Project coverage is 74.78%. Comparing base (3a3e36e) to head (361dd0c).

Files with missing lines	Patch %	Lines
test/control_filters/test_rate_limiter.hpp	92.30%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           ros2-master     #237      +/-   ##
===============================================
+ Coverage        71.05%   74.78%   +3.73%     
===============================================
  Files               20       22       +2     
  Lines             1040     1071      +31     
  Branches            84       85       +1     
===============================================
+ Hits               739      801      +62     
+ Misses             255      222      -33     
- Partials            46       48       +2     

Flag	Coverage Δ
unittests	74.78% <97.61%> (+3.73%)	⬆️

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

Files with missing lines	Coverage Δ
include/control_filters/rate_limiter.hpp	73.07% <100.00%> (+73.07%)	⬆️
include/control_toolbox/rate_limiter.hpp	73.01% <ø> (+4.76%)	⬆️
test/control_filters/test_load_rate_limiter.cpp	100.00% <ø> (ø)
test/control_filters/test_rate_limiter.cpp	100.00% <100.00%> (ø)
test/control_filters/test_rate_limiter.hpp	92.30% <92.30%> (ø)