MP/Skirmish - Tech Level Limit

[dunk2k]

Describe the feature you'd like
Option in Skirmish/multiplayer lobby to limit Tech level for match.
Tech Level Limit value cannot be less than Tech Level Start value.

Describe why do you think it is needed

1. Match modifier for those that do want to have weapons and structures from higher tiers; in same manner structure limits can be used to make No VTOL/Cyborg/Tank matches.
2. Could be used:
   1. To assist with balancing and/or further segmentation of tech levels
   2. For training purposes; help new players get feeling for where/when tech levels begin/end.