Flop exceptions related to invalid inputs should result in 400 Bad Request

[a3kov]

Is your feature request related to a problem? Please describe. Currently if you pass invalid filter value, for example, you get error 500. 400 would be more appropriate.

Describe the solution you'd like Exceptions should have plug_status property set:

defexception [:message, plug_status: 400]

Describe alternatives you've considered

Additional context