Remove Topdoc

[Scotchester]

GitHub is reporting that this repo has a vulnerability in uglify-js, which is several levels down our dependency tree. (We now use uglify-es for our actual uglification.) The root dependency that leads to uglify-js is grunt-topdoc, which we no longer use in this project.

Removals

• grunt-topdoc dependency and its associated Grunt tasks and templates

Testing

1. Pull branch
2. rm -rf node_modules/
3. Run ./setup.sh and verify that everything works correctly

Checklist

• [x] Changes are limited to a single goal (no scope creep)
• [x] Code can be automatically merged (no conflicts)
• [x] Code follows the standards laid out in the front end playbook
• [x] Passes all existing automated tests
• [x] New functions include new tests
• [x] New functions are documented (with a description, list of inputs, and expected output)
• [x] Placeholder code is flagged
• [x] Visually tested in supported browsers and devices
• [x] Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)