Refresh datasets based on new lists

[briatte]

• [x] electorate.*-.rds
• [x] electorate-counts.tsv
  • [x] plot-coverage.r (uses data from electorate-counts.tsv)
  • [x] coverage.rmd (uses data from electorate-counts.tsv)
  • [x] plot-choropleths.r (uses data from electorate-counts.tsv)
• [x] panel.tsv and panel.rmd
• [x] councillors.tsv
• [ ] Google Sheets for coding votes