Add options to hide/modify default toolbars

[krzysztofMlczk]

When integrating Excalidraw it would be great to allow devs to hide/replace existing toolbars or at least have control over what happens when each option gets clicked. Here is a screenshot of what should be configurable:

Currently the is no native way to opt out of the predefined UI.

[alexandertam15]

Also - I need a feature to make the top toolbar/side menu toolbar text bigger. Control + should make the toolbar text size bigger as well.

I can barely see what the toolbar is saying as it's so small on my external monitor. Competitor Draw.io has this feature.