Unify beyond ridiculous Snowflake Searocks duplication gore, refs rP11137.

The island generation code was copied once for

• the small mapsize and 2 players
• the small mapsize and 3 players
• the small mapsize and 4 players
• the small mapsize and more than 4 players
• the medium mapsize and up to 4 players
• the medium mapsize and more than 4 players
• the normal mapsize and up to 5 players
• the normal mapsize and up to 7 players
• the normal mapsize and 8 players
• the large mapsize and up to 5 players
• the large mapsize and more than 5 players

Within each of these copies there were three copies of the island createArea+placer+painters call and
about 10 unreadable island connection setter copies.

Support mapgenerations with only one player.
Cleanup createAreas calls as in rP20301 and broken indentation.
Fix missing forests due to a missing parentheses in the forest count of that commit.