Re-add buttons for switching editor mode between View/Both/Edit

[ErikMichelson]

Which part of the project should be enhanced?

Editor / Appbar

Is your enhancement request related to a problem? Please describe.

We've got some feedback via the community forum and also personal, that the View/Edit/Both mode toggle buttons from HD1 were really useful and that removing them in HD2 is a regression. The replacement arrow buttons aren't bad per se, but hidden unless hovered and also a "moving target" without a fixed position, thus leading to worse UX.

Describe the solution you'd like

Re-add the requested buttons, but keep the arrow buttons on the slider as well.

Describe alternatives you've considered

An earlier design draft incorporated "maximize" buttons in each pane for switching to their full view. However this seems to suffer the same UX problem.

Additional context

No response