Option to list rendering backends

[Meakk]

Fix #1697

Add information about available rendering backends

[github-actions]

You are modifying libf3d public API! ⚠️Please update bindings accordingly⚠️!
You can find them in their respective directories: python, java, webassembly.

[codecov]

Codecov Report

Attention: Patch coverage is 96.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 95.67%. Comparing base (7a649d4) to head (3c5e377).

Files with missing lines	Patch %	Lines
library/src/engine.cxx	92.30%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1831      +/-   ##
==========================================
- Coverage   95.67%   95.67%   -0.01%     
==========================================
  Files         125      125              
  Lines        9821     9844      +23     
==========================================
+ Hits         9396     9418      +22     
- Misses        425      426       +1     

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[snoyer]

would need to use --rendering-backends-list (plural) to match --readers-list and --bindings-list
However I believe the singular is grammatically correct so the other 2 would need to change instead/eventually?

[mwestphal]

small changes needed

[mwestphal]

small question