Changes to quarto docs

These are items noted in PR #796 . That PR was pulled in as the mechanics work and these are cosmetic and other changes that should be made before releasing CDM v5.5

• link to annual symposia on background page to be updated
• update dates on the cdm refresh process page
• update CDM WG meeting information
• Remove links to google drive location on refresh process page
• Remove link to running agenda on refresh process page
• all links in documentation need to be moved to the CDM v5.5 pages when available
• A good task for 2027 would be to review all old documentation (from 2021) to make sure it still holds up and we agree with the message
  • For example the patient privacy article heavily refers to HIPAA, we need to add EHDS as well
• Patient privacy page references are in bibtext format, we need to figure out how to update these for quarto
• Custom concepts page - I think there is a poster from Roger we might need to add in there as reference
• The second and third columns in the CDM table descriptions need to be widened to accommodate the text better
• tooling support page needs correct emojis and all tables included -> to be updated for upcoming v5.5
• CDM additions - accepted changes needs either to be removed or a correct link
• update era table scripts (issue already open for this)

Start by reviewing PR #796 and the listed background, CDM refresh process, CDM WG, patient privacy, custom concepts, CDM table descriptions, tooling support, and CDM additions pages. Bring the documentation links, dates, references, tables, emojis, and v5.5 content up to date, while leaving the separately tracked era table scripts issue out of scope.