Trenches, medical stations, supply depot's

[Genrizza]

In the next couple of updates, it would be awesome to get the ability to construct trenches on the front lines, and well as Medical stations (like a frontline hospital for repairing troops and supply depots. 

Trench- give AT, Dug-in tanks, and troops a huge immunity to artillery fire and bombers (because both are extremely OP in frontline combat) and give a buff to defense against ground units

Field Hospital- a place where soldiers can get repaired (maybe even give us a field repair station, and airstrip for repairing vehicles and airplanes)

supply depot- a place that distributes supplies to units in a specific area, like a circle. The supplies must be shipped from cities or league cities. (This isn't OP because supply lines can easily be cut if not defended properly) and if destroyed the destroyer gets the supplies stashed there.