Build Options as Config object

[DevNico]

Allow configuring build options on the Mapper or even MapType level. For example the option ignoreNullableSourceField could be useful for a subset of mappings but currently would need to be enabled for the entire package. I'd propose adding something like a AutoMapprConfig object which could be assigned to Mappers / MapTypes to enable/disable build rules.

[tenhobi]

Sounds good to me!