e2e API testing tool

We want to test API endpoints continuously. For that we can write a tool based on the stream tester
that will be doing that.
It will:
1. Do new signup with new email
2. Will read verification email and get verification link from it
3. Will follow verification link
4. Will login (get authentication token same as frontend does)
5. Will create new API key
6. Will transcode couple of segments using HTTP push with new key
7. Will create new stream using API key
8. Will stream 1min stream using RTMP
9. Will delete key and a stream
10. Will check usage

If anything will go wrong it will report errors to the Discord

Start by reading the existing stream tester, then map how it could drive the listed signup, verification, authentication, API-key, transcoding, streaming, cleanup, and usage checks. Done means the workflow runs continuously and reports any failure to Discord, but the issue does not name files, tests, or a specific entry point.

Written by the indexing model from the issue text.