Add documentation for collision check

[JuliusMiller]

Description

Add documentation for Collision check

Fixes #127

Type of change

• Documentation

Does this PR introduce a breaking change?

No

Most important changes

collision_check.md

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works (might be obsolete with CI later on)
• New and existing unit tests pass locally with my changes (might be obsolete with CI later on)

[github-actions]

Simulation results

Metric	Value
Avg. driving score	0.005892
Avg. route completion	0.02
Avg. infraction penalty	0.348058
Collisions with pedestrians	0.0
Collisions with vehicles	0.0
Collisions with layout	709.196
Red lights infractions	0.0
Stop sign infractions	0.0
Off-road infractions	0.001
Route deviations	0.0
Route timeouts	709.196
Agent blocked	0.0
Yield emergency vehicles infractions	0.0
Scenario timeouts	709.196
Min speed infractions	0.0