Add four open souce transportation projects

[fiftysevendegreesofrad]

https://github.com/fiftysevendegreesofrad/sdna_plus
https://github.com/fiftysevendegreesofrad/BayesianDrape
https://github.com/fiftysevendegreesofrad/TrafRed
https://github.com/fiftysevendegreesofrad/UKRailFlows

The projects are :

• [ x] Active
• [ x] Documented
• [ x] Licensed with an open source license
• [ x] Shows usage from external parties
• [ x] Directly targets environmental sustainability

Find more details in the Contribution Guide.

All listed projects on OpenSustain.tech will be supported via multiple community services:

1. Issues labeled as Good First Issue will be visible on ClimateTriage.com. This is a great way to welcome new community members to your project.
2. All new projects listed will be posted on our Mastodon and Bluesky channel.