Create frontend API functions for user secrets #843
Description
Related to #781, but as long as we know the API contracts, it's not necessarily blocking.
Context
This should be a relatively simple issue. Once the backend API methods are defined, we need to make sure that we have TypeScript equivalents defined in the frontend. (As a reminder, the API file is not code-genned, and will need to be written manually).
If this work is started before #781 is done, we can set up the API functions to return mock data.