Add user setting to hide vote counts
This MR adds a checkbox on the user settings page to hide vote counts in the UI. All vote counts are hidden, including the vote counts on the current user's topics and comments as well as other users' topics and comments.
I did not hide vote counts in tildes/tildes/templates/topic_listing.rss.jinja2
or tildes/tildes/templates/topic_listing.atom.jinja2
since I'm unsure as to whether they are within the scope of this setting.
Implements #780