[Merged by Bors] - Fix documentation links

[Razican]

This PR changes the following:

• Adds a new (very simple) security policy, to comply with GitHub standards
• Changes the internal links of the documentation to point to the new boajs.dev domain
• The developer documentation link now lies in the CONTRIBUTING.md file

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	94,277	94,277	0
Passed	71,092	71,092	0
Ignored	17,324	17,324	0
Failed	5,861	5,861	0
Panics	2	2	0
Conformance	75.41%	75.41%	0.00%

[codecov]

Codecov Report

Merging #2741 (ab44082) into main (e9daa3d) will increase coverage by 0.14%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #2741      +/-   ##
==========================================
+ Coverage   50.25%   50.40%   +0.14%     
==========================================
  Files         399      397       -2     
  Lines       40122    39937     -185     
==========================================
- Hits        20165    20131      -34     
+ Misses      19957    19806     -151     

Impacted Files	Coverage Δ
boa_ast/src/lib.rs	75.00% <ø> (ø)
boa_engine/src/lib.rs	78.20% <ø> (ø)
boa_gc/src/lib.rs	100.00% <ø> (ø)
boa_interner/src/lib.rs	82.35% <ø> (-1.69%)	⬇️
boa_profiler/src/lib.rs	66.66% <ø> (ø)
boa_unicode/src/lib.rs	69.69% <ø> (ø)

... and 18 files with indirect coverage changes

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[HalidOdat]

bors r+

[bors]

Pull request successfully merged into main.

Build succeeded:

• Build and Test (macos-latest)
• Build and Test (windows-latest)
• Coverage
• Misc