`properties` parameter: Support similar syntax as DANTE

[stefandesu]

DANTE supports several additional syntax options for the properties URL parameter:

• Only -: Should return minimal fields only, but I think we can ignore it.
• Only *: Should return all default and additional fields. We should support this as well.
• Prefixed + (i.e. +narrower): Should return default fields and all listed fields. Since we don't omit any fields, we only need to support the syntax. (Currently, it will read this as requesting the property +narrower, therefore not returning the narrower property.)
• Prefixed - (i.e. -altLabel): Should return default fields minus the listed fields. In this case, we can consider implementing the functionality if there's a use case that needs to save on data. Otherwise we could just ignore the whole properties parameter for now because we're not removing anything.