Danger label models

The label models a package must carry, by model number (5.2.2.2.2); "None" means no label is required. These codes appear in Table A column 5; ADR sets them out in section 5.2.2.2.2 of ADR 2025 (ECE/TRANS/352). 21 codes are in use, 0 reviewed. Each meaning below is a paraphrase in FreightUtils' own words, not the official text.