Improve handling cqrs handlers errors (exceptions, request/operation result implementation)

[adamskibicki]

nick chapsas's video as an example

[adamskibicki]

After analysing there is no reason to implement it now - waste of time. Exception throwing for errors (validations and others etc.) for now is enough, if i need to handle form of error http response of how specific exception is handled i can do it in exception handling middleware.

[adamskibicki]

After analysing it is implemented to avoid breaking code flow with throwing exceptions - easier to track in VS.