[Court] Resolution should handle removed jurors

[c410-f3r]

By @sea212 at #248 (comment)

Two concerns:

1. The account that was removed from the court has no chance anymore to unreserve it's reserved funds, since the exit_court dispatchable, which is the only dispatchable that unreserves the reserved currency of a juror, will result in an error, because the juror in question cannot be found anymore.
2. What happens with other votes the juror submitted? Let's assume the juror is part of 4 court cases. In the first case (1) the juror is marked as Tardy. In the second case the juror misbehaves again, therefore the juror is removed from the court. However, the juror might have already voted for case 3 and case 4.

A potential solution might be to remove the account from the jurors and add it to a "dismissal" list, which contains accounts that cannot vote anymore, but might receive additional penalties for votes already cast.

This brings me to another question: The jurors who voted for a losing outcome and get 50% of their bond slashed are still part of the court. Does this mean that during the next case, they will have only 50% of their initial bond on stake? And the fifth time they lose (without belonging to the losing majority), it's only 0.5.pow(5) = 0.03125 of the initial bond that's on stake? I think we have to discuss this corner case.