feat: add frontend api service (EN-305)

Summary

A frontend api service to abstract away all axios logic and have it contained to a location to be reused throughout the React application. Implements fully typed classes with methods on them to hit every backend endpoint.

To Test/Use

1. Import the relevant class for the resource (i.e. apiApplications for applications, apiUsers for users, etc.)
2. Call the appropriate method on the class (i.e. getAll to query all of that resource, post to create a new one of that resource, etc.)

Note: Everything is fully typed, so you should be able to refer to the typings for what/how to pass things into each method.