Timeline should support non-trackpad

[jasonjmcghee]

If a user is not a trackpad user (e.g. closed laptop + PC mouse) they should still be able to navigate timeline.

I propose:

• if an external mouse (with wheel?) is connected, scroll up to go back and down to go forward in time.
• arrow keys left and right should support back and forward in time.

[jasonjmcghee]

Thanks to @mkielo3 for reporting. Any interest in tackling this feature?

[mkielo3]

Sure, happy to take a crack at it

[MartinN3]

Oh damn i thought it wasn't working for me, but you just need to scroll with touchpad! 🥇

There definitely needs to be at least hint of what to do, i tried every key on keyboard.

Thanks.