[Outlook] outlook_cloud: Graph contacts + distribution lists

## Parent

Part of #4264
Blocked by: Graph calendar sync

## Summary

Implement Graph contacts and distribution-list / contact-group sync with parity to current Contact and Distribution List document shapes.

## Scope

- Contacts API + contact groups / DL mapping
- Golden tests for Contact + Distribution List doc types

## Acceptance criteria

- [ ] Contact and Distribution List docs match golden contract
- [ ] Unit tests green

## Out of scope

- Tasks, attachments, DLS, incremental

Start by tracing the existing Contact and Distribution List document shapes and the Graph contacts/contact-groups mapping; account for the stated dependency on Graph calendar sync. Add golden tests for both document types and run the unit suite; done means both docs match the golden contract and tests are green.

Written by the indexing model from the issue text.