CDF-557- Wmo Accessibility and validation improvements

[mo-AlexFord]

JIRA: CDF-557 Description: Integrate QoL changes from MO codes registry and improve validation and accesibility scores where possible

Live version can be explored here - https://puce.dev.wmo.reference.metoffice.cloud/

• [x] Fix contrast errors & labels and other disability fixes for important aspects (Entry labels, functional aspects of the website)
• [x] Fixed various tabbing issues & default SPARQL queries, added copy URI button
• [x] Removed dead pages and updated menu options