Add custom score shortcut buttons for X01

[mischkadb]

[mischkadb]

I want them to be somewhat customizable.

1. Focus on latters. Especially the row below the numbers or a block of letters (e.g. Q-E, A-D, Y/Z-C)
2. A few shortcuts on the Numpad, e.g. /*-+ (remember that one of those is reserved for remaining score option)

We should avoid F-keys. I know that N01 uses those, but in a browser they have default functions that could be overwritten, but shouldn't. Letters are available, so let's go for those.