LUM-1543: Add whitelisting endpoint

[shyam-patel-kira]

Changelog

Added new whitelist system allowing users to request getting whitelisted

• Created Whitelist model with user relationship and boolean status flags
• Added schemas, queries and service layer for whitelist operations
• Implemented user endpoints (POST/GET /whitelist) for request submission and status checking
• Added admin endpoints for approval management (GET/PATCH /whitelist/admin/{user_id}/*)
• User authentication via API key with appropriate permission checks
• All changes follow existing codebase patterns and include proper error handling
• Manually tested all endpoints with Postman
• Added user endpoints to postman

[linear]

LUM-1543 customer api updates to request whitelist access, grant whitelist access, list/manage/etc whitelist access

[vasrap]

So the way this should work is, a whitelist request will be a CP submitting their info (name, email, phone, etc), and a list of addresses (one for each node). And an endpoint to cancel an existing whitelist request. I think that's all that's needed. So the db relationship will be User (1) -> CP (1) -> Addresses (N). If the whitelist request is cancelled, there can be a user_cancelled field in the CP table to set to true, ie don't delete records to retain their info. If they re-request whitelist, we can set that to false, and replace the addresses they provided before with new ones. I don't think we need admin endpoints, we can edit fields in the db manually initually, since we'll have to whitelist them manually in the contract anyway.