Extend collection of rooms for Room Builder

[sadko4u]

A good question found on Ardour forum:

https://discourse.ardour.org/t/lsp-room-builder/107519

It would be nice to extend the collection of different low-polygonal rooms for the Room Builder.

[sadko4u]

Good candidates:

• Stairment with 4 floors;
• Car tunnel;
• Closed car parking;
• Forest with road;
• Forest without road;
• Maya pyramid;
• Town square;
• Churches;
• Cathedrals;
• Theaters.