Cleanup of the code

[Getslow6]

Hi,

I'm not too experienced in Python, but over the coming period my plan is to create a pull request that adds update entities to your integration - as my personal goal would be to easily manage all my docker containers using your integration!

This PR contains some simple changes that I've made while familiarizing myself with the code. I tried to split them in clear separate commits. It's my first online PR outside some software related experience in my previous job, so if there are do's/don'ts or feedback I'm all ears!

Also: I've removed the find_rename function, as it is no longer used. This also implies that the rename dictionary in the configuration.yaml no longer works if people would set it up without the UI. Do you want me to make changes to the README accordingly?