feat: add dt plugin

[booniepepper]

Summary

Description:

• Tool repo URL: https://github.com/so-dang-cool/dt
• Plugin repo URL: https://github.com/so-dang-cool/asdf-dt

Checklist

• Format with scripts/format.bash
• Test locally with scripts/test_plugin.bash --file plugins/<your_new_plugin_name>
• Your plugin CI tests are green

[jdx]

your build image is broken when I render the readme: https://github.com/so-dang-cool/asdf-dt/workflow/Test/badge.svg

it should be this:

[![Build](https://github.com/so-dang-cool/asdf-dt/actions/workflows/build.yml/badge.svg?branch=main)](https://github.com/so-dang-cool/asdf-dt/actions/workflows/build.yml)

[booniepepper]

Oops, thanks for catching. Updating

[jthegedus]

Thanks