Support battery draining start via topics

[nkoenig]

🎉 New feature

Summary

Tracked vehicles were recently added and the implementation does not allow a battery to start draining. This PR is copied from @peci1 hot fix here: peci1/subt#2. Need by this SubT PR: osrf/subt#958

A test has been added and some documentation to the system's header file.

Test it

The new test should be self-explanatory.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge

[codecov]

Codecov Report

Merging #1255 (f88afb0) into ign-gazebo4 (c473a08) will increase coverage by 0.27%.
The diff coverage is 93.33%.

@@               Coverage Diff               @@
##           ign-gazebo4    #1255      +/-   ##
===============================================
+ Coverage        66.41%   66.69%   +0.27%     
===============================================
  Files              250      250              
  Lines            19256    19270      +14     
===============================================
+ Hits             12789    12852      +63     
+ Misses            6467     6418      -49     

Impacted Files	Coverage Δ
src/systems/battery_plugin/LinearBatteryPlugin.cc	63.01% <93.33%> (+21.98%)	⬆️
src/Server.cc	84.33% <0.00%> (-0.61%)	⬇️

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[osrf-triage]

This pull request has been mentioned on Gazebo Community. There might be relevant details there:

https://community.gazebosim.org/t/new-ignition-releases-2022-01-10/1228/1

[osrf-triage]

This pull request has been mentioned on Gazebo Community. There might be relevant details there:

https://community.gazebosim.org/t/new-ignition-releases-2022-01-24-citadel-edifice-fortress/1241/1

[osrf-triage]

This pull request has been mentioned on Gazebo Community. There might be relevant details there:

https://community.gazebosim.org/t/new-ignition-releases-2022-04-13-fortress-edifice/1367/1