Instant run-off elections

[BenBals]

closes #220 closes #81

[frcroth]

Can you merge main into this? Makes testing easier

[jeriox]

* For me the poll list is not shown in the menu?

did you tick the "show in menus" checkbox? otherwise probably menu caching again

  What should I review here if the calculation is not in yet?

data model, vote casting, esp. if there are some cases that I missed, like the one with restricting POSTing that you already mentioned

[frcroth]

The menu item is now shown, might have also been a problem on my side. Data model looks ok

[coveralls]

Pull Request Test Coverage Report for Build 7887481246

Details

• -51 of 259 (80.31%) changed or added relevant lines in 8 files are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.05%) to 74.429%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
myhpi/tests/polls/test_ranked_choice_algorithm.py	54	55	98.18%
myhpi/polls/forms.py	0	23	0.0%
myhpi/polls/models.py	123	150	82.0%
<!--	Total:	208	259	80.31%	-->

Files with Coverage Reduction	New Missed Lines	%
myhpi/polls/models.py	4	82.89%
<!--	Total:	4		-->

Totals
Change from base Build 7886409057:	-0.05%
Covered Lines:	1435
Relevant Lines:	1928

---

💛 - Coveralls

[BenBals]

What's left to do:

as_sensible_datastructure performs an individual database request for each and every ballot. We expect vote numbers to be (at most) in the low thousands. Still, we should prefetch this data in calculate_votes.

Relevant code:

    def as_sensible_datastructure(self):
        result = []
        for entry in self.rankedchoiceballotentry_set.all():
            result.append((entry.rank, entry))
        heapq.heapify(result)
        return result

and

    def calculate_ranking(self):
        ballots = list(map(lambda x: x.as_sensible_datastructure(), list(self.ballots.all())))
        options = self.options.all()
        [snip]

[jeriox]

* Could add some spacing between the vote button and the footer
  ![image](https://private-user-images.githubusercontent.com/6863832/303944516-b25f82dd-2276-4566-a519-5b82e0ad530e.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.M6ys4GXmkg6BReRX01UhvnrhU2MiRu7JwYJuK-e2T2A)

@SilvanVerhoeven