T431817 Add queries and documentation for Wikipedia ve citation metrics

Contributor checklist

• I have checked all files included in this merge request for data that should not be publicly released
• Code formatting and conventions are in line with the WMDE Analytics contributing guide
• All changes from the main branch have been rebased into this branch

Description

• T431817: Adds the queries needed to track citations
  • Manual and automatic citations broken down by Wikipedia, temporary status and newcomer status
    • Also includes manual citations via the fallback method on automatic citations
    • Also includes various totals so we can understand various parts of the funnel
  • Includes a full Mermaid diagram for the flows involved as well as what the various features and actions are for the stages
• Note: This MR also removes two columns from the wikipedia_newcomer_ve_reference_funnel_monthly process that aren't used in other parts of the query