Allow ketchup to be used by all our versions of superset

[antonatem]

Old releases of superset had the package name superset while the new releases are named apache-superset as noted here https://pypi.org/project/superset/.

Superset has moved to apache-superset, as of 0.34.0 onwards, please pip install apache-superset

In ketchup's setup.py file, the minimal requirement is superset and for the newer versions, it would be apache-superset.

This requires an edit to the install_requires values to support both by either:

1. Adding a script to check which superset is installed then assign it to a variable that will be used by install_requires
2. Remove the minimal requirement of having superset(testing if this will work)

[ukanga]

I would go with changing to only require apache-superset in setup.py. We should be installing tagged versions of ketchup. In this case, when merged, we should tag a new release. There is no need to maintain backward compatibility with old superset versions.