It shall be possible to delete through a REST endpoint any non-normative interface type definitions.

Create a new class for interface definition related endpoints and add an endpoint for deleting interface type definitions (there will be more endpoints added by coming stories). The implementation of the endpoint will probably be able to follow the same pattern as the recently introduced method for deleting data types in DataTypeServlet (https://gerrit.onap.org/r/c/sdc/+/133371)

In order to be able to distinguish between normative and non-normative interface definitions, a new field called 'normative' shall be added to InterfaceDataDefiniton class in a similar way to was added to DataTypeDataDefinition in https://gerrit.onap.org/r/c/sdc/+/132977. The setting and persistence of this field shall also follow a similar pattern as was introduced in that story for data types.