Enable specification for RCV ruleset

[umbernhard]

Currently, the Arlo RAIRE module supports San Francisco's IRV ruleset. However, other jurisdictions use different ruleset. Maine, for example, handles skipped rankings and termination of the tabulation slightly differently. Specifically:

• If 2 or more rankings on a ballot are skipped, the ballot is exhausted, whereas in SF each ranking is "slid up" to the next spot, so if the ranking was "1, 4" it would become "1, 2" while in ME the ballot would be exhausted and the second vote would not count.
• Maine continues the IRV algorithm until there are only two remaining candidates, with the candidate with the most votes winning. SF stops tallying as soon as any candidate has a majority of the votes. Technically I believe these two tabulations are equivalent, but we should vet it more thoroughly.

In order to support additional IRV rulesets, the way we normalize CVRs will need to change to accept different rulesets and adapt accordingly: https://github.com/votingworks/arlo/blob/2cdf47d7ec71177f6e0796542b6ce554b1d6aece/server/audit_math/supersimple_raire.py#L101-L144

[umbernhard]

Additionally, we need a way to specify which ruleset should be used per-audit. This could be a simple lookup based on the jurisdiction ID, or it could be specified by the AA during audit setup. For Arlington, I think we should go with the former.