[OI-233814] Game creation UI

1) Also proposal, as most people bad at remembering numbers and for human nature is more easy to deal with words instead,
please make seed to be not numeric, but letters \ words -- so people can share their worlds more easily, and you can just add convert method from letters to numbers to get your end value.

I propose to remove those buttons and instead add title: "Customize your game starting conditions".

3) Also it will be better if cancel and start game buttons are located in same row and be same size (start game on right and cancel on left)and instead of one above another