Add BikeTag API playground

[KenEucker]

There is an existing project of code: https://github.com/KenEucker/biketag-playground

That code has been used to resolve data issues with Imgur or Sanity and handle importing/exporting and mass updating of BikeTag data. These are functions that should only be available to a super admin, not individual BikeTag Ambassadors, but the Playground itself should include simple API interactions to get tag data which is accessible to all people who log in to this app.

[KenEucker]

The biketag-playground project will grow to include two different focuses: the API (biketag-api) and then the Vue component library (biketag-vue), and should include the code necessary for both projects.

This code can be copied for the interim, but will need to be incorporated into the monorepo as described here, once that has been set up: KenEucker/biketag-api#86

[KenEucker]

The BikeTag Playground should be implemented as a VuePress website, as we will now be using VuePress for documentation across all @biketag packages.