{Feature request} Add customisable touch control

[ansinerd]

Greetings, On larger devices like 11inch or 12.9 inch iPads the fixed touch control is a bit painful to play with, usually when you are on the go, having an option to customise, move and resize the on screen touch buttons would massively improve the experience on larger devices. PPSSPP has great customisation option available for on screen touch controls, inspiration can be taken from there.