Delete non-existing unboxed DSUB HD connectors

Delete non-existing unboxed DSUB HD connectors

The manufacturer (RS) that offers "unboxed" DSUB connectors in single density does not seem to offer them for high density.

There are other manufacturer with "unboxed" HD DSUB connectors, but those are using different dimensions, different datasheet etc.

Part from other manufacturers might be added later, but it would be best to delete non-existing parts for now.

See: !1073 (merged), !1084 (merged). I split this out of a bigger merge request to make it easier/faster to merge.

@cpresser