[Plaza Streets] Treat plaza streets as paved streets

[Starjon]

Currently, plaza streets are treated as dirt roads for the purposes of building range and vehicle speed. Could you change this so that they are treated as paved streets? I tried to do it myself, but unfortunately couldn't get it to work.

[Starjon]

After finding another mod that adds new streets which are treated as paved streets ("More Streets Available" by "Yodel Kindergarten"), I could get it to work: Starjon@1b5eb5c It's probably not the most elegant solution and for now I only did it for the promenade street, maybe I will do it for the other streets, too. I also didn't add any stone costs, which some might want for balancing reasons. If you want me to create a pull request for the promenade on it's own, I can do that.