[FEATURE]: Hunt down and remove all `unwrap`

[NYBACHOK]

Feature description

We have unwraps in our code. They should be removed

[dmvict]

I guess that here we have to apply some convention. Something like:

• unwrap's should be replaced to expect's if we have reasons to unwrap without handling the error
• unwrap's should be replaced to panic's with proper error messages for the other cases
• if it is possible, change signature of a routine to handle error properly

Let's discuss these points. I'm trying to make the issue clear and more concrete.

[NYBACHOK]

Remove most of the easy ones, but there are still some which require more time.