I think the idea of a Macro is probably general enough across a range of file formats that we could add it as an embedded type
However, there's actually 2 levels to an OOXML macro. The OOXML file contains a binary vba project bin file, and within that is the actual macro text + its properties. Maybe we should have the ooxml extractor first expose a `application/vnd.ms-office.vbaProject` embedded resource, then we use a second parser which extracts a body of the macro vbscript as text/x-vbasic with the other macro properties/attributes (name, sid, various boolean flags) as metadata?
eg application/vnd.ms-excel.sheet.macroenabled.12 -> application/vnd.ms-office.vbaProject -> text/x-vbasic + metadata