Replace flask testing with requests-wsgi-adapter

[eruvanos]

Following the setup of FastAPI it is much easier to use a request wsgi adapter, than starting a server on each test!

https://pypi.org/project/requests-wsgi-adapter/

• add requests-wsgi-adapter as test dep
• replace serve tests with mounted requests client

[eruvanos]

Or use httpx, which comes with wsgi support out of the box and supports request api