[web]: Generate user API schema and integrate

[davidgamez]

Describe the problem

In this issue, the user api replaces the current retrieveUserInformation and updateUserInformation TS functions.

Proposed solution

GET upserts app_user on first call (replaces retrieveUserInformation Firebase callable). PUT updates profile (replaces updateUserInformation). Firebase callables with REST calls to /v1/users/me. Update signUpSaga to call the new API.

Alternatives you've considered

No response

Additional context

No response