Make diff_drive_controller a ChainableControllerInterface (fixes #1457)

[arthurlovekin]

Using dea3d3c as a reference, I made the diff_drive_controller into a ChainableControllerInterface. I used a RealtimeBuffer to handle the incoming velocity command messages, and I also added lifecycle checks and support for the speed_limiter that were not included in dea3d3c. I also added some tests that run the chainable controller in unchained mode, and I intend to test it in chained mode in one of my current projects (though I couldn't readily figure out how to make this into a test).

[christophfroehlich]

Please always install pre-commit to avoid failing tests ;) otherwise, run it manually with pre-commit run --all

regarding tests: have a look at the mecanum controller, it is chainable anf there are exactly those tests already available

[arthurlovekin]

I've fixed my formatting by running pre-commit run --all-files and added a test for chained mode, using the mecanum controller as a reference.

[codecov]

Codecov Report

Attention: Patch coverage is 75.18248% with 34 lines in your changes missing coverage. Please review.

Project coverage is 83.96%. Comparing base (0736e6c) to head (a353628).

Files with missing lines	Patch %	Lines
...iff_drive_controller/src/diff_drive_controller.cpp	67.08%	23 Missing and 3 partials ⚠️
...ive_controller/test/test_diff_drive_controller.cpp	86.20%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1485      +/-   ##
==========================================
+ Coverage   83.86%   83.96%   +0.10%     
==========================================
  Files         122      121       -1     
  Lines       11139    11241     +102     
  Branches      945      951       +6     
==========================================
+ Hits         9342     9439      +97     
- Misses       1487     1488       +1     
- Partials      310      314       +4     

Flag	Coverage Δ
unittests	83.96% <75.18%> (+0.10%)	⬆️

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

Files with missing lines	Coverage Δ
...ive_controller/test/test_diff_drive_controller.cpp	93.28% <86.20%> (-1.92%)	⬇️
...iff_drive_controller/src/diff_drive_controller.cpp	68.75% <67.08%> (-2.44%)	⬇️

... and 7 files with indirect coverage changes