Change Election Rules to deal with multiple noms

[tfpk]

This change is designed to explicitly deal with the issue of people nominating for multiple positions.

It:

• Requires that people preference their nominations when nominating. That means, if you nominate for GEDI and President, you have to say which one you would prefer.
• Removes the requirement that first and second preferences should be treated as first preferences for CSESoc's election (NOTE: this is because there's no calculator that can do it easily, and it's kind of unclear)
• Adds an algorithm for electing people which means that elections for president are run as two seperate elections (one election, then a second one that excludes the winner of the first)
• Makes it clear how to deal with people who nominate for multiple positions.
• Adds a big explanatory note, because this is hard.

I'm genuinely tempted to write a paper about this.

~tfpk

[piddlingtuna]

The references to 'Grievance Officer' will cause merge conflicts with #49. Arc also mentioned they had an issue with "In the case of no member being nominated for the position of Grievance Officer, the incoming executive will have a vote to appoint one of themselves as a Grievance Officer." copied from the current constitution but #49 is also deleting this.

[piddlingtuna]

This was approved at the AGM.