DO NOT MERGE - Tests not working - WIP!

So after founding out, that #search method in CustomersController contains a lot of business logic, I decided to split it and move it to services.

In the main CustomerService class, I decided to write #perform method in high-level style, so the code will be more understandable.

I found out, that search by entity and search all entities using the same queries, so I moved it to one place and re-using it, so if we changed something, we will update only one place, and also it's much easier to de-bug if there is a bug somewhere.

I also note, that we have limit parameter, but we using it only in the view layer. I didn't do anything here, since I don't know the whole logic and how should it work, but If I do it from scratch or fully rewriting - I'll move limit to queries, so I'll already take from database limited records, because (it's really bad) if we have 1 million records - we will take all of them and only limit them on view layer.