Add dungeon level generation

Add a dungeon level generator, which:

1. generates an infinite sequence of rectangular rooms within the
   dimensions of the level
2. removes any duplicates from that sequence
3. Generates a graph from the delaunay triangulation of the centerpoints
   of those rooms
4. Generates the minimum-spanning-tree of that delaunay triangulation,
   with weights given by line length in points
5. Adds back a subset (default 10-15%) of edges from the delaunay
   triangulation to the graph
6. Uses the resulting graph to draw corridors between the rooms, using a
   random point on the near edge of each room to pick the points of the
   corridors

package.yaml

@@ -30,14 +30,19 @@ dependencies:
 - containers
 - data-default
 - deepseq
+- fgl
+- fgl-arbitrary
 - file-embed
 - filepath
 - generic-arbitrary
 - generic-monoid
 - generic-lens
 - groups
+- hgeometry
+- hgeometry-combinatorial
 - JuicyPixels
 - lens
+- linear
 - megaparsec
 - MonadRandom
 - mtl
@@ -49,6 +54,7 @@ dependencies:
 - raw-strings-qq
 - reflection
 - Rasterific
+- streams
 - stache
 - semigroupoids
 - tomland