Object deletion shortcut accessibility

[rvneXe]

Hi. I already know that removing objects is possible by using MMB, Shift+RMB and Del. But since osu is being played by a wide variety of different hardware, making those options more accessible will make the life easier.

I'm using "myself" as an example; Using a 60% Keyboard and a Tablet. None of those options is available for me, since Tablet Pen doesn't have RightClick (if we use it with osu!lazer built-in driver) and I have to use Fn combinations of my keyboard to press Del.

• Backspace
  Every single keyboard, does come with a Backspace, regardless of its layout. and also, there's no default bind for it in the game's settings.

• Tablet pen keys
  They're bindable in Key Configuration settings, but can't use it for object deletion.

• An option in Key Configuration settings (Best idea in my opinion)
  What if we could assign a custom key? All of options above will be available then.