SIP-33: read contacts

[fabiobozzo]

This PR introduces SIP-33, which proposes a new RPC method snap_getContacts that allows Snaps to access contacts from a user's MetaMask address book.

Key features:

• Introduces a new permission snap_getContacts that grants read-only access to contacts
• Returns contact data including name, address, and optional metadata (future proof)
• Enables user-friendly workflows by letting Snaps leverage existing contacts, instead of custom per-Snap address books managed via snap_manageState

This feature would benefit users by eliminating the need to manually copy/paste addresses and allowing Snaps to provide more personalized experiences like recipient selection from contacts, contact-based notifications, and improved transaction insights. The implementation focuses on security and privacy, ensuring users have clear visibility into what contact information is being shared.