Voting: tokens held by an app count towards the vote quorum in that org

[john-light]

If tokens have been assigned to the Finance app, those tokens count towards the quorum. Since the Finance app cannot vote, it's counterintuitive that those tokens would count towards the vote quorum. If the Finance app holds a large amount of tokens, this could make it impossible for a vote to ever pass.

[sohkai]

This is a problem for all of an organization's apps, and not just the Finance app. Holding tokens in the Token Manager is also susceptible to aragon/aragon-apps#537.

In the case where an organization wants to hold its own token, we should change the frontend so that it only allow users to assign tokens to an Agent app, and no other apps.