Add examples

[JonasScholl]

          > Let's keep it simple. No hosted docs. People use it or they don't. We can't invest that much. At least as long as Tebuto isn't live 😄

hmm yes the repo is probably not big enough to invest the effort 😄 Should we then just have the examples in an own folder with README.md files and link them in the main readme? Like

README.md
examples/
    fastapi/
       README.md
       app.py
       ...
    pytest/
       README.md
       conftest.py
       ...

I think having the examples as real subprojects is more beneficial than having them in the readme - it's more readable and people can fork it more easily

Originally posted by @JonasScholl in #21 (comment)