Add description to each params for openapi

Also, we can add a small comment to each params to describe what it is. [Sources...](https://quobix.com/vacuum/rules/descriptions/oas3-parameter-description/)

I don't think we should put a lot of effort on this one, but can still be relevant.
I'm also wondering, what about querystrings/body.. We should probably also add comments, but didn't found any rules about it.

_Originally posted by @Defferrard in https://github.com/graasp/graasp/pull/1523#discussion_r1802662262_

Maybe we want to register even small units (eg `captcha`) so the description is uniform?