feat: hotfixing steering for leaderboard

[hellschwalex]

Description

Since all Tuning, Testing etc for Acting (Steering in particular) was done in dev.launch with perfect Sensors, the very well tuned PurePursuit Controller would be expected to outperform in the leaderboard-enviroment aswell. This is NOT the case (and we do not know why exactly).
Bringing back Stanley Controller (with a new, softer tuning to regard Sensor-Flickering) for velocities of 6+ m/s and retuning PurePursuit Controllers amplification factor (from 4.75 to under 1, again to regard Sensor-Flickering) should highly increase driving score.
Again I do not exactly know, why the well-tested and goodworking tuning from dev.launch does not work in the leaderboard. So this is a rather "dirty" hotfix (but it works).

Fixes #216 (issue)

Type of change

• PurePursuit amplification factor retuned for leaderboard
• Stanley is back, retuned for leaderboard

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	0.19351
Avg. route completion	8.01
Avg. infraction penalty	0.02413
Collisions with pedestrians	1.691
Collisions with vehicles	7.609
Collisions with layout	0.845
Red lights infractions	0.0
Stop sign infractions	0.0
Off-road infractions	0
Route deviations	0.0
Route timeouts	0.0
Agent blocked	1.691
Yield emergency vehicles infractions	0.0
Scenario timeouts	2.536
Min speed infractions	0.0

[robertik10]

Seems to be working!