Add new PR template

[nvkelso]

• Store the data in {state|state>county}/{year} path structure
• Update STATE or COUNTY readme to indicate:
  • source of the data
    webpage it was downloaded from OR contact of data provider if received over email or snail mail
  • when the data became active (YYYY or YYYY-MM or YYYY-MM-DD)
  • which elections the data was active for
• Optional: include screenshot of the data in the PR so other people can see it easily.