Allow datapacks to add incompatible warnings

[catter1]

There are many people who report issues with the map when using Tectonic and Terralith together, when they need to use Terratonic instead. I suggest creating a standardised file to be included inside of datapacks that the map website can read. In that file, it could outline the datapacks it doesn't work with (i.e. Tectonic has a warning to not be used with Terralith). If the map website detects the warned datapack present, it will present the user with a warning, and perhaps a recommendation to use the correct datapack (if applicable).

[jacobsjo]

This seems like something that should maybe be a smithed convention? I've also had ideas about using weld in the future for this kind of compatibility.

(Sidenode: part of the problem here is that Terratonic doesn't show up in the "Open from Modrinth" menu, since its labeled "utility" and I filter mods with those out, that's something I wanted to adress anyways.)