Remove the commit interval option as it is espacially for kafka
streams. Instead use the configurations option, which takes key
value pairs and set these as environment variables for the UC.

The order of the environment variables is atm crucial for the
run uc py.

Add the hierachie structure to the kubernetes workload generator
files.
Use the new structure in the run uc scripts.

Reorder the structure of the use cases to use a base and customize
this accordingly to their needs.