Add mappings for missing numpad keys

[s1hofmann]

Short overview
Mappings for several numpad keys are missing:

• numlock
• scrollock
• add
• subtract
• divide
• multiply

[smithkyle]

There seems to be a mismatch somewhere with NumLock - when I use Key.NumLock I get an error:

Error: [nut.js] - Error: Invalid key code specified.
    at Object.libnut. [as keyToggle] (/Users/ksmith/dev/nutjs-test/node_modules/@nut-tree/libnut-darwin/permissionCheck.js:68:96)

But if I use Key.NumberLock, I don't get an error...I'm not sure if it's actually working correctly or not, though...

This is on macOS 12.4