add cancel button to GameInputView

[akeschmidi]

[Shock9616]

Hey! Thanks for the contribution! I just have a couple of things that I'd like to ask you to fix:

Firstly, the buttons are not centred when adding a game, and the save game button is getting cut off when editing a page (see below images)

Secondly, @jxhug suggested on Discord that rather than a cancel button at the bottom, we use an X button in the top left like regular window controls. Could you try adding that instead?

Thanks again! We really appreciate your contributions!

[Shock9616]

Closing for inactivity