Support physical keyboard shortcuts

[Kelvinlby]

I often use this app on my tablet with a mouse and a keyboard, and I find it inconvenient to cut/copy/paste files/folders without Ctrl+x/c/v.

[Kelvinlby]

Handle keyboard shortcut

[zhanghai]

Another interesting thing: https://stackoverflow.com/questions/71062697/register-hardware-keyboard-shortcuts-in-androids-help-menu