refactor!: porting frontend code to using react

[bcoe]

Someone recently asked for a new feature to Wombat Dressing Room (the ability to lock down publication to specific npm tags), and it motivated me to first dust off the codebase and migrate to using a front-end framework.

1. partially as a learning experience.
2. in an effort to make sure our front-end is well tested.

Here's how it looks

Help page

Login page

Token management widget

Token creation page

Here's the state of frontend testing

tldr; we now ue React and have pretty good test coverage of the components.

Fixes #13