Make `pylint` check for Google style imports

[leandro-lucarella-frequenz]

We can use the package pylint-google-style-guide-imports-enforcing to make pylint check the import style, as we want to follow that style but we hardly do because there is no enforcement.

[llucax]

Soft-blocked on:

• Evaluate if we want to use google-style imports or not #56

It would be good to see how this check works and how code that passes this check looks like as part of the conversation.