[Example App] Make identity & contact

This MR includes !9 (merged), !11 (merged), and !12 (merged) (make sure to merge them before reviewing this MR)

• Implement creating and previewing my identity in example app.
• Add makeContactFromIdentity functor to Client.
• Implement creating and previewing my contact in example app.

requested review from @ahmedshehata01

assigned to @darrarski.xx

mentioned in commit a65d6542

merged