Used to generate position files for some manufacturers like JLC.
Also in this patch:
- Now position files are naturally sorted (R10 after R9, not after R1)
- Position files in CSV format quotes only the columns that could
contain an space. Just like KiCad does.
- Fixed: Generic filter `include_only` option worked only when debug
enabled.
- Now is a separated filter type (`var_rename`).
- Now all variants support a `pre_transform` filter list.
- An internal `_var_rename` filter is defined (default).