Detekt: Add Custom detekt rule

[igorwojda]

We could write custom detekt rule.

It can be any rule, but one example that comes to my head is rule that verifies clean architecture layers (verify dependency rule correctness) - make sure that class defined in ...domain layer does not uses any classes from other layers (have imports from other layers).

Another idea would be the rule to Verify that every class that extends androidx.lifecycle.ViewModel class has ViewModel suffix

Also maybe we could also add tests for this rules 🤔

More:
https://arturbosch.github.io/detekt/extensions.html
https://proandroiddev.com/writing-custom-lint-rules-for-your-kotlin-project-with-detekt-653e4dbbe8b9
https://medium.com/@vanniktech/writing-your-first-detekt-rule-ee940e56428d