ghidra: some 16-bit enums should have 32-bit versions #32

There's any number of enums (e.g. job_type) that we have defined as 16-bit but which are often handled internally as 32-bit. Having them defined only as 16-bit enums makes marking up decompiled code harder.

import_df_structures should therefore probably create a 32-bit version for any enum that is officially sized as 16-bit.