Feat: update V2 and V3 vault docs

[rossgalloway]

• Add Diagrams for v2 and v3 vaults
• Simplify User Docs pages for v2 and v3 vaults
• Move more developer focused info to developer docs sections
  • V3 periphery Contracts
  • developer-centric links
• Create v2 landing page.
• Move v2 Factory page to dev docs.
• Added new "yearn" admonition type for informational copy.
• Added new yVaults Faq and migrated Vault token info into it.
• Added product banner images to V3, yCRV, and yPrisma.