Add actionable platform example

[akenyon]

Simple example demonstrating use of actionable platforms. Gives an intro to the platforms and movement controllers currently available in Stone Soup.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.28%. Comparing base (4b6bd37) to head (ad3b52d).
Report is 119 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1077      +/-   ##
==========================================
- Coverage   94.31%   94.28%   -0.03%     
==========================================
  Files         208      208              
  Lines       13603    13603              
  Branches     2767     2767              
==========================================
- Hits        12830    12826       -4     
- Misses        522      524       +2     
- Partials      251      253       +2     

Flag	Coverage Δ
integration	67.22% <ø> (+0.02%)	⬆️
unittests	90.39% <ø> (-0.03%)	⬇️

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[csherman-dstl]

Some minor readability suggestions, the other suggestion would be to try and separate each line to not exceed character limit.