Feature: maxViewDistance, maxViewDistanceAtDark moved into ruleset

Update of https://github.com/SupSuper/OpenXcom/pull/698
A bit rewritten.
To make it clear, if cloud of smoke reduces visibility in 4 times (i.e. from 20 to 5 tiles), then after increasing maxViewDistance (i.e. 100 tiles) this cloud of smoke also will reduces visibility in 4 times (from 100 to 25 tiles).