chore NET-1404: remove deprecated package request from autocert-* (#2996)

## Summary

Package `request` has been deprecated since 2020. Removed its usage from
sub-packages `autocertifier-server` and `autocertifier-client` and
replaced with with native `https` module's request functionality.

Also made test
_packages/autocertifier-server/test/integration/RestServer-real-http-client.test.ts_
exercise the new HTTP requesting utility in `autocertifier-client` to
gain more test coverage confidence.

I tested the certificate fetching process by hand by creating a new
cloud instance and installing this branch there. My node was
successfully able to get a subdomain and cert assigned to itself by the
production autocertifier-server.

## Future improvements

Use built-in node.js `fetch` instead of `https`. However, see the
discussion of this PR as to how this needs to be approached.

Author: harbu