frontend: allow users to upvote or downvote projects
    
    This change will show a reddit-style upvote and downvote
    buttons next to the project name. It is implemented in a way
    that we can see the sum of a project score as one number but
    we can also see the number of upvotes and downvotes separately
    because even though the overall score of a project might be high,
    if there is considerable amount of downvotes, there might be
    something fishy about it.
    
    The score and voting is available to be seen by an anonymous
    user, however cliking on a upvote/downvote button will redirect
    him to the login page.