Add a hotkey to pause listening to new movements

[RduMarais]

I implemented this feature so I could use the eraser when drawing.

What is going on :

• I added a check in both read_tablet functions tp pause the incoming events using a shortcut.
• The shortcut is fetched using lib keyboard
• You can define your shortcut using --hotkey argument.
• By default, no hotkey is defined
• you can use all key codes available here

What could be improved

• I implemented it, but did not test with evdev
• keyboard uses a lot of imports, there are probably lighter libs that could be used.
• This branch also use a fix for MacOS I found in #82 and proposed in #83

[Evidlo]

Can pynput be used instead of keyboard for this? It is already a dependency of this package.

[Evidlo]

Bump