Note we don't cast negative votes when users remove their support. That
way we provide compatibility for institutions who have implemented real
negative votes (in case there are / will be any), and we also keep the
database meaningful: it's not that users downvoted something; they
simply removed their upvote.
Co-Authored-By: Javi Martín <javim@elretirao.net>
Co-Authored-By: Julian Nicolas Herrero <microweb10@gmail.com>
Since we're going to add an action to remove supports, having a separate
controller makes things easier.
Note there was a strange piece of code which assumed users were not
verified if they couldn't vote investments. Now the code is also
strange, since it assumes users are not verified if they can't create
votes. We might need to revisit these conditions if our logic changes in
the future.
