Voting Core Migration

[abluey]

Summary

Close #404

Checklist

• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

• Have you tested the changes? (pytest & dpytest)
• Have you followed PEP-8 for naming and styling?
• Has your code been properly documented with RestructuredText docstrings?
• Have you added your changes to CHANGELOG.md under the [Unreleased] heading?
• If your code added new bot commands, have you updated documentation.json?

• All of this code is your own, or follows the author repo's licence.