feat: Implement Origin/Destination matrix

[shenriotpro]

Description

(I'll fix the commit message after reviews.)

This is the first useful version of this feature. There is still some room for optimization, but it seems quite fast so far (2s for the medium example). Note that some trainruns don't have any endNode on this example.

Issues

close #269

Checklist

• This PR contains a description of the changes I'm making
• I've read the Contribution Guidelines
• I've added tests for changes or features I've introduced
• I documented any high-level concepts I'm introducing in documentation/
• CI is currently green and this is ready for review

[shenriotpro]

@louisgreiner @jacomyal

[louisgreiner]

Thank you for the excellent documentation that makes this new feature easy to read. The code is also very cleaned

I just wonder if some variable names would not be better if they could be more explicit. I commented a few things about that, feel free to ignore if it adds too much noise.

Overall high quality code, it needs to be challenged by the users. Next step is implementing an interface and optimizing

PS: the test unit is very good 🥇

[aiAdrian]

Very nice work!