Prevent proposals not being approved due to lack of citizenship engagement

[hhh01398]

Problem:
In order for a proposal to be approved through delegated voting, the total number of positive delegated votes needs to be larger than a threshold percentage (by default, 50%) of the total citizen population. This may often not be the case because not enough citizens appoint seated delegates due to lack of engagement.

Solution:
To alleviate the problem, we propose to change the Assembly smart contract code so that, in order for a proposal to be approved through delegated voting, the total number of positive delegated votes needs to be larger than a threshold percentage of the citizen population represented by the seated delegates, instead of the total citizen population.

[hhh01398]

Implementation and info here: #31