Add sorting functions on survey response columns

[Herover]

Description

This PR adds some sorting on survey responses viewed in lists.

Screenshots

Many options

Single option

Free text

Changes

• Free text responses are sorted alphabetically with the browsers locale compare, meaning order can change depending on browser language.
• Many options are sorted by number of options selected.
• Single options are sorted by selected or not

Notes to reviewer

A smartlist that adds people who responed to "A very open survey" has all the kinds of columns implemented.

Related issues

Resolves #2508

[ziggabyte]

Hi! I tried this out on a list where i added people who had responded to the "cheese survey", and also added people based on a different criteria. When I tried to sort the list based on the survey response columns when there were more people in the list, it did not behave really as I would have expected.

You can look at the list I used here and try sorting it, to see the buggy behaviour: /organize/1/people/lists/59

Do you wanna take a look and see what this behaviour is about, and see if you can fix it? :D

[Herover]

Thanks for the feedback, I didn't consider testing with people who had not answered a survey. I hope it looks better now!