Rearrange CLI command names

This is meant as collection of suggestions to be discussed. My main points are:

1. I find the terms "install" and "uninstall" confusing. This is setting up a database schema, not really installing new software.
2. I find the namespaces not helpful.

This pull request goes together with https://github.com/wmde/WikibaseQueryEngine/pull/98.
As explained in my email to you, I think this is wrong