Add a new batch of themed rooms for 10.0

[copperwater]

• "xnh" letter shape room
• Room in the shape of a cat face
• Regular Honeycomb: single hexagonal beehive room (also, just an empty hexagonal room). use the two hexagonal bigroom as a scale model
• Chasm - filled with open air (one pool-style, one vertical crack-style, only at high level difficulty. there could also be one with a 3x3 magic platform surrounded by a 2-wide ring of air surrounded by normal floor, or possibly no floor)
• Square room similar to "crossed X of water" but with fixed dimensions and a fountain in the center. Or adjust "crossed X of water" so it only puts a fountain in the center when the dimensions are both odd.
• submerged room (fill): room full of water with sea monsters and a chest of treasure (not containing a magic lamp). This was planned for xnh9.0 but removed because of a couple vanilla bugs preventing it from happening.
• room with crenellated walls
• steal from unnethack: pacman room
• room with several wands, but they all have only 1-3 charges left
• Elliptical room (maybe vertical one too)
• Elliptical ring room (the height of "Ring, medium" but stretched horizontally
• Triangle room in all 4 orientations
• X-shaped room (not the same as "four-leaf clover")