[ext/preset-discovery] missing copyright/vendor string for collections

[defiantnerd]

clap_preset_discovery_collection_t should support a copyright string and/or a vendor string.

• the vendor might not be the same as the plugin vendor
• the copyright string might be an artist reference

[abique]

So if the collection needs more metadata, does it also need a creator or this is already implied by the presets? Is the copyright a preset attribute or a collection attribute? Do you have examples what the copyright may look like? Do we need a set of constant strings for this?

Vendor -> OK.

[abique]

I think the copyright is more a preset attribute than a collection attribute. In which case it should be passed using set_extra_info("copyright", "blah"); We need then to specify what strings can be set to copyright.