Add Layer button

[EHuangg]

Is your feature request related to a problem? Please describe

It's annoying to right-click and then have to find add new layer in the menu pop-up

Describe the solution you'd like

I want there to be an extra button in the timeline section that just adds a new layer

Describe alternatives you've considered

I could use the shortcut Ctrl+Shift+N, but I'm terrible at remembering all of the shortcuts, and this would make it easier for new users.

Additional context

It would go right here next to the other buttons

[EHuangg]

I've taken the liberty of making the icons

default:

classic: