Feature request: Separation of `cms check`

[wolfga...@fotopuzzle.de]

Currently, `cms check` does 2 minor things: It checks the configuration of your system, e.g. settings and checks the database for errors, e.g. plugins, contents, etc.

It would be nice if these 2 things are separated from each other. So with one command, you check your configs etc. and with the other you check the database its contents.

For example: `cms checkconf` and `cms checkenv`.

I am having a test-runner script with docker which sets up a self-sufficient test-environment and runs the given tests.

When I add `cms check` to this, I need a fully functioning database with all the migrations applied to it.

As this is a self-sufficient test-environment I don't have "real" data inside the database and therefore checking the content of it doesn't make sense to me.