Feature request - Soft tab deleting and inserting

[mzivic7]

When there are only spaces on left side of blinking cursor:

• If backspace is pressed: remove one soft tab, but always delete exact number of spaces so there are no excess spaces.
• If tab key is pressed: add exactly 4 spaces, and move cursor to first non-space char on right - I don't need cursor in middle of tab.

For example: If I press backspace, it should delete 4 spaces. But now if I add 3 spaces, they don't represent tab, nevertheless backspace should delete those 3 spaces, so number of spaces are again multiple of 4. If I press tab key, it should insert 4 spaces, but it inserts 2.

Note: I assumed tab to be 4 spaces, but that number can already be changed in settings.