Create initial admin user with password and API key for REST API

[mloskot]

Ubuntu 18.04
Package: api-umbrella
Version: 0.15.1-1~bionic

My goal is to do the following during provisioning of a server with API Umbrella setup:

1. Initialise the service with initial/default admin user
2. Use the REST API to pre-configure the API Umbrella with API backends and API users with keys.

From the docs, I've learned how to create the initial super

web:
  admin:
    auth_strategies:
      enabled:
        - local
    initial_superusers:
      - admin@example.com
    username_is_email: true

and the user gets created but it is not usable:

1. No password is generated and blank password is not accepted, and it is not documented if it's possible to enable it.
2. No API key is generated to be used as the X-Api-Key: header value.
3. Only authentication_token is created, which I assume is for use as the X-Admin-Auth-Token: header value.

The issue 1. has been also asked about in #439 (comment)

As I have learned from #368 (comment) and #439 (comment), I can query the MongoDB directly:

$ /opt/api-umbrella/embedded/bin/mongo 127.0.0.1:14001/api_umbrella --eval "db.admins.find().pretty()"
MongoDB shell version: 3.2.22
connecting to: 127.0.0.1:14001/api_umbrella
{
        "_id" : "2ff988a5-b087-4d3a-9326-c3285feb0214",
        "updated_at" : ISODate("2020-09-24T15:55:19Z"),
        "username" : "admin@example.com",
        "authentication_token" : "z2S0DyE4vZDWtznq6jZAqeT4fW1hVVzTvuSZaBYf",
        "registration_source" : "seed",
        "created_at" : ISODate("2020-09-24T15:55:19Z"),
        "superuser" : true
}

In this old issue @brylie asked "How do I access my auth token and admin API key?" which is a question close to mine but @darylrobbins explained in #135 (comment) how to generate the authentication_token which apparently had not been generated in old versions of the API Umbrella due to missing implementation fixed in NREL/api-umbrella-router@fa10065

That solution does not apply to my case as my initial_superusers get the authentication_token generated.

Is there a similar mongo trick to generate the API key for X-Api-Key:?
How to create superuser non-interactively in order to pre-configure the API Umbrella service via the REST API in non-interactive manner?