postgres: automatically set schema permissions - #216

There are a lot of logic requests and each of the requests may not be failed, transactionality is needed here, quite significant changes. We don't cover it with unit tests and it doesn't really make sense to do it, but we have to understand what this logic does perfectly, and have a guarantee that either a number of requests are failed or we rollback and return error message.

I understand that you would like to add these changes, if you take these risks on yourself and describe how it will work when one of the requests is not executed correctly, then I think we can try to add these changes. And this is a rather dubious improvement, if others have such code in their product, it does not mean that we should follow their mistakes.