ByteTrack: Remove BaseTrack, refactor, add types, remove dead code, moved out Shared Kalman

[LinasKo]

Description

The code of ByteTrack is messy and hard to read. I've given it some attention to bring it closer to our repo standards. Behaviour is identical to previous iteration.

The primary goal is more clarity.

• Moved STrack to single_object_track.py
• Moved out all class variables, shared among instances of STrack, causing potential clashes between different ByteTrack instances. In this case - that's the shared Kalman.
• Clarified a few variable names and types

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How has this change been tested, please provide a testcase or example of how you tested the change?

Colab: https://drive.google.com/file/d/1vloWTAb0nylZNm7CU7pXONh2pKUbVc2w/view?usp=sharing

Any specific deployment considerations

Notify others working on tracker about conflicts.

Docs

• Docs updated? What were the changes:

[LinasKo]

Hey @onuralpszr, I'm adding you as an optional reviewer.
Feel free to have a look if you have the time and motivation.