Add documentation

[doc-E-brown]

• Remove unimplemented function from VoronoiDiagram trait
• Add documentation for voronoi_diagram file
• Add benchmark tests for alternate delaunay triangulation methods.

The results of the bench mark when executed on my machine are:

Delaunay Triangulation  time:   [2.2839 µs 2.3687 µs 2.4780 µs]
                        change: [-21.682% -14.728% -7.0971%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 1 outliers among 100 measurements (1.00%)
  1 (1.00%) high mild

Spade Unconstrained Triangulation
                        time:   [1.4216 µs 1.4831 µs 1.5582 µs]
                        change: [+39.411% +46.250% +53.808%] (p = 0.00 < 0.05)
                        Performance has regressed.
Found 7 outliers among 100 measurements (7.00%)
  5 (5.00%) high mild
  2 (2.00%) high severe

Constrained Outer Triangulation
                        time:   [3.5185 µs 3.7830 µs 4.1260 µs]

Constrain Triangulation time:   [3.5962 µs 3.7355 µs 3.8970 µs]
Found 15 outliers among 100 measurements (15.00%)
  2 (2.00%) low mild
  4 (4.00%) high mild
  9 (9.00%) high severe