Redesigns the test.toml to use a list instead of a directory
additionally it is now possible to do toml and matrix tests on singular
files as well as on a subset of files.
Fixes: #851
Change-Id: If8635109c6274f406ad68fe35315b9125f45f67d
Add Documentation for usage and development within functional2
including common fixtures and where to find them
This is done to make the migration from functional easier and give devs
a reference for how one writes tests
Change-Id: I6ee73e654d245fd4ad43e495d1172e406313cb23