Fully infer object mapper without a class body

[stefankoppier]

Is your feature request related to a problem? Please describe.
When writing a mapper without any explicit mappings has a lot of boilerplate. For example, in

object MyMapper : ObjectMappie<Something, SomethingDto>() {
    override fun map(from: Something): SomethingDto = mapping()
}

the map function declaration is boilerplate.

Describe the solution you'd like
Writing object object MyMapper : ObjectMappie<Something, SomethingDto>() should be sufficient, and equivalent to a map body without any explicit mappings.