Try to replace our custom integrity tests (explicitly callable) with similar Substrate tests

[svyatonik]

I've recently learned that the Substrate has its own integrity tests, which are a part of the pallet Hooks. They add an autogenerated test to the runtimes, where the pallet is used.

We have our own integrity tests, which need to be added explicitly to the runtime - types assertions, weight checks and so on. Could we possibly move all our tests (or at least some parts) to pallet hooks? It'll make integration easier - integrity tests is what is sometimes forgotten when the bridge is configured.