Add option to more backspace button to the left

[cfernhout]

Is your feature request related to a problem? Please describe.
I'm always frustrated when I need to reach the 0 bottom with my right thumb that it's quite far.

Describe the solution you'd like
Adding an option to move the backspace button completely to the left (below 1) and moving the 0 to below the 2 and the dot to below the 3 buttons.

Describe alternatives you've considered
I'm coming from a Samsung Galaxy phone and am frustrated about the layout of the default calculator on my pixel, that's why I've switched to OpenCalc. I assume others will have this as well. Therefore, it's better to have it as a customization option instead of something fixed.

Additional context
The layout of the Samsung Calculator