Ruins from the historical 10 Kingdoms period of the Reachmen

The ruins should be based on the Broch, which is a type of cylindrical building made from stacked stones from the iron age in Scotland.

The idea would be that these Ruins can be used as historical markers, as well as locations for dungeons or small reachmen encampments.

They should function quite similarly to velothi towers in placement/execution.

Needs esp and collisions.

An additional SetAnv stair to replace the current scaled up one leading down to the Marina docks

This is admittedly somewhat pedantic, but:

- Fixed the normals on the connecting edges of 03 so that they're seamless with the other pieces again
- Mirrored the UVs of the newly added trim on one side of 02 so that it's the right way around
- Fixed the slightly inconsistent normals on the sides of 01
- Switched the tiny bit of trim that's on the inside corner of 04 back to the trim texture

Unique texture shamelessly stolen from the purple scrub replacer asset