Progress on implementing the About screen

[TheoPannetier]

Fixed:

• Call the graphical display about_view #433

Tests for:

• Class about keeps track of the game version #596
• about contains a link to the GitHub repo #599
• about contains a link to join the Discord server #598

I believe some have been addressed already by eager juniors, so the tests arrive a bit late 😅

[codecov-commenter]

Codecov Report

Merging #649 (f118c35) into develop (0f830bd) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop     #649      +/-   ##
===========================================
+ Coverage    88.10%   88.12%   +0.02%     
===========================================
  Files           49       49              
  Lines         2270     2274       +4     
  Branches       172      172              
===========================================
+ Hits          2000     2004       +4     
  Misses         270      270              

Impacted Files	Coverage Δ
about.cpp	100.00% <100.00%> (+100.00%)	⬆️
main.cpp	94.11% <100.00%> (+0.11%)	⬆️
read_only.h	33.33% <0.00%> (-50.01%)	⬇️

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[OggyOggelito]

I approve these changes! Good work Theo