Instead of a fixed size that don't work at all for bigger screens.
Other tweaks:
- Use the value-land dimens to vary 'extra_horizontal_margin'
- Move label size to Config, because it can change at runtime (rotation)
- Slightly decrease the size of "long" symbols
Depending on the pixel density isn't ideal for a keyboard, which would
render differently depending on the "scaling" accessibility option.
Landscape mode needs a special values. At the same time, increase the
horizontal margin when landscape.
This was a half-finished feature:
- Dangerous when typing passwords
- Caused crash on some devices
- Ugly (on its own but also blinking when sliding and not fixed in size)
