Starting age tech Option in Random Map Start-up

[Harchie Hirondo]

I think that it would be nice if a new option is added before starting a new random game. This option shall enable the player to select what shall be the starting age tech in game.
This could also benefit AoD as well, since they span a large timeline.
Having to start from the earliest era will likely result to long games. Adding an option to toggle what era the game shall begin with, can also modify the length of such games.