🇧🇪 Add Belgian data

[Mind-the-Cap]

Data	Where and when
Mobility survey	Available from the MONITOR project (2016), but apparently not published for the federal survey (2025)
Flows	Available from the MONITOR project (2016), but representativity has to be checked; apparently not published for the federal stats (every 3 years)
Modal shares	By municipality (2005-2021), detailed modes by region (2022-2023)
Local population	By municipality, binary gender and age, by statistical sector (2025)
Local jobs
Socio-professional categories & house composition
Car ownership	By statistical sector (2024)

[FlxPo]

The MONITOR mobility survey (2016) seems to have open detailed data : https://www.enquete.vias.be/fr/mobilite/monitor/

[Mind-the-Cap]

Very good catch, it seems to have quite everything we need, with detailed trips of the participants in the trips csv and even all the moves within these trips (including the model of car used!)
Adding it to the table, that makes Belgium a very good candidate for the next country choice ✨🍻