Ranked choice block

Add a block that allows for Ranked Choice Voting - a list of options that the user can rank in order of preference.

I like implementations where the user is presented with a list of options, and can drag to rearrange them in order of preference, or simply tap them in order of preference. There should also be a state where a certain option isn’t picked at all. Typically this can be done with e.g. separator in the list - only the items above the separator are considered chosen (in order of preference) and the rest aren’t part of the answer - or visually presented as two lists with a vertical separator.

This is a good visualization of the idea:

https://www.opinionx.co/order-rank

On the answers database level, it shouldn’t differ much from multiple-choice, except that order of choices recorded matters.

It can also be implemented as an option for Matrix block to only allow one selection per column (1st choice, 2nd choice, etc.). It would be simpler to implement since the UI element is already there, but to me that’s less intuitive UX for the user and can be unviable when there’s a lot of choices.

The actual ranked choice vote tally is not in scope of OpnForm — needs only provide input for further processing.