Update Documentation guideline for IDs

[leskneebone]

The VocExcel Documentation tab gives examples of how to make an ID for each concept. The examples include minting an ID based on skos:prefLabel for a concept ("Rhode Island Red" could be "rhode-island-red" or "rir").

The guideline should be updated to prioritise robust ID patterns. As a prefLabel may be updated, an ID suffix based on a superseded prefLabel could be misleading. Further, if multiple prefLabel data is added to a concept in other languages, the ID will only align with one prefLabel.

The guideline already mentioned an increment method. Possibly UUID approach could be mentioned, with reference to a minting service (such as https://www.uuidgenerator.net).