Issue 1619 RFE: dirt and gravel roads

[psikomonkie]

Resolves #1619
Resolves #5595

Contains new graphics for gravel roads (from stonewall072) and dirt roads (Morkath)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 28.99%. Comparing base (458ae46) to head (1ddd055).
Report is 12 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6246      +/-   ##
============================================
- Coverage     28.99%   28.99%   -0.01%     
- Complexity    13982    13984       +2     
============================================
  Files          2652     2652              
  Lines        268282   268314      +32     
  Branches      47762    47773      +11     
============================================
+ Hits          77799    77805       +6     
- Misses       186601   186627      +26     
  Partials       3882     3882              

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[HammerGS]

Do we need art for this?

[psikomonkie]

Do we need art for this?

No & Yes.

No, we don't need art for this to function. Currently a dirt road and gravel road look the same, but they function as they're supposed to.

Yes, I think we'll want art for gravel.

I do not think we should hold off on merging this PR until we have gravel road art as the gravel roads art is purely decorative and won't effect the functionality of this. Gravel & Dirt roads should not show up during map generation, they should only appear if a map maker uses it.

[psikomonkie]

Now includes art for gravel and dirt roads. Dirt roads use the art made by Morkath for #5595 and gravel roads use art made by stonewall072 for #1619

Thanks!