In UX, back/cancel/etc buttons usually go on the left, while forward/confirm/etc go on the right. (Note that even the icon for "Back" is a leftwards-pointing arrow.) STK put the Back arrow button on general screens in the upper left corner, but before this commit, put back/cancel/etc on the right in dialogs and such. This commit fixes things to be in line with standard UX conventions, and also in line with the pre-existing upper-left corner Back button placement on screens in STK.
https://ux.stackexchange.com/a/63239
* Open the confirm dialog if exiting the grand prix editor with changes by escape key
* When launching the tutorial, use the last used device instead of the first keyboard
* When launching story mode, use the last used device instead of the first keyboard
* Make the kart color selection dialog more consistent with other dialogs
Includes:
* Add an icon button bar with containing actions to apply changes or to cancel them
* The kart only shows its straight frame, without animation; it is slightly smaller
* Adjust the vertical space between widgets, to try keeping the kart size larger
* Use a button bar for the video settings and custom camera settings dialog
