SPEC: Use of `EAN` for barcodes is too specific

[madpah]

There are a number of standardised barcode formats beyond EAN (where in-fact EAN has at least two standards itself: EAN-13 and EAN-8).

We should consider removing references to EAN and replace with Barcode or such to be appropriately generic.

FYI @oej @vpetersson

From https://github.com/CycloneDX/transparency-exchange-api/pull/77#discussion_r1850135912

[vpetersson]

I actually already squeezed in that fix. However, there might be a better word for this than barcode.

[madpah]

@oej - should we discuss the terminology used here in relation to Barcodes?

[oej]

Good thing to have on the agenda.