Setup this repo as a Typescript package

There are a few things to do before we can start developing properly here with regards to using typescript and having some form of CI/CD

TODOs:

• Choose a node version (10) - this repo will not produce executable javascrtipt, it'll only contain types that other packages can use so it doesn't matter if we use a different version of node to the rest of pubsweet.
• Set up build/lint/prettier config - This is pretty much a copypasta task
• Set up the CI - so that we don't break everything every time we merge anything
• Write the types - they're already written in a MR in pubsweet, we just need to move them here
• Deploy the package to npm - it's probably going to be called @pubsweet/types
• Configure the CI pipeline to enable CD