add interactor for profiles controller

[tyranja]

In order to make the code in the controller more readable, I started to use interactors.

I used the interactors to encapsulate logic and move it out of the controller. This has the advantage that it can also be tested separately.

https://github.com/collectiveidea/interactor
https://medium.com/@lucaspolonuer/ruby-on-rails-boost-your-software-design-skills-with-interactors-e07f1f9a711e
https://blog.saeloun.com/2020/05/06/rails-using-interactor-gem/

[zaziemo]

I like the interactors and did not know them before :) Let's try it out!
Everything seems to work, I only have some minor improvements and questions.

[zaziemo]

good work :)