Standarize IDs

[kaizu]

Follows identifiers.org like "https://identifiers.org/kegg.compound:C12345".

[kozo2]

• All KEGG objects have identifiers.org ID
• escher has BiGG metabolite and reaction IDs in identifiers.org. But escher does NOT have identifiers.org ID for the metabolic pathway
• wikipathways has the pathway ID in identifiers.org

[kozo2]

• [ ] Requesting the escher identifiers.org ID https://registry.identifiers.org/prefixregistrationrequest