don't limit server max sides

there are 2 reasons why the maximum side number is limited in some
contexts:
1) The map format can only store 9 starting positions
2) only the first 9 sides have default colors.

However, 'color' and 'starting position' are both sideproperties that
can explicitly given by wml if needed. And the server doesn't use any of
them, so i see no reason why the server should reject them.