Jinja helper for election results

[LukeMoll]

To help with consistent table layout, formatting, etc around results of elections (AGMs, EGMs), it would be nice to leverage Jinja's macros and filter abilities to do the work for us. This likely won't be completed before the 2022 AGM.

Features this could include:

• Automatically displaying RON and Spoiled/Empty ballots as 0, even if not provided explicitly
• Sort AV candidates by votes, with RON always at the bottom
  • This brings up an interesting case; what is shown when two candidates have the same number of [first choice] votes? How can we make the workings of AV clear in this case?
• Generating the OM election STV table. The input to this should be considered; does it need all of the raw ballots? or just each candidate's vote total at each stage?
  • Show quota and equivalent votes in the header of each stage -- perhaps on a separate line to avoid wide columns
  • Candidates have often been sorted by name in STV elections
• Automatically total votes in the table headers
• Optionally display percentage of total votes next to each candidate