[services] Backup - Blob Put Client - Add essential objects

Summary:
Depends on D5004

Adding necessary imports and objects that we're going to use in the put client.

Test Plan: backup builds

Reviewers: jon, tomek, varun, max

Reviewed By: jon

Subscribers: ashoat, tomek, atul, abosh

Differential Revision: https://phab.comm.dev/D5005