Extract "About Boa" section into a separate file

[jedel1043]

This makes it easier to keep that section in sync with all crates.

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	94,657	94,657	0
Passed	73,917	73,917	0
Ignored	17,505	17,505	0
Failed	3,235	3,235	0
Panics	0	0	0
Conformance	78.09%	78.09%	0.00%

[codecov]

Codecov Report

Merging #2938 (cc7f209) into main (eb37614) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #2938      +/-   ##
==========================================
- Coverage   52.09%   52.06%   -0.03%     
==========================================
  Files         435      435              
  Lines       43713    43692      -21     
==========================================
- Hits        22771    22749      -22     
- Misses      20942    20943       +1     

Impacted Files	Coverage Δ
boa_ast/src/lib.rs	75.00% <ø> (ø)
boa_cli/src/main.rs	0.76% <ø> (ø)
boa_engine/src/lib.rs	78.20% <ø> (ø)
boa_gc/src/lib.rs	100.00% <ø> (ø)
boa_icu_provider/src/lib.rs	100.00% <ø> (ø)
boa_interner/src/lib.rs	84.03% <ø> (ø)
boa_macros/src/lib.rs	0.00% <ø> (ø)
boa_profiler/src/lib.rs	66.66% <ø> (ø)
boa_tester/src/main.rs	0.00% <ø> (ø)
boa_unicode/src/lib.rs	66.66% <ø> (ø)
... and 1 more

... and 5 files with indirect coverage changes

[Razican]

Thanks!

[HalidOdat]

Looks good to me! :)