[Services] Export client-base-reactors as CMake Project

Summary: Needed for backup and blob service

Test Plan: Run test plan from https://phab.comm.dev/D4494

Reviewers: karol, max, atul

Reviewed By: atul

Subscribers: ashoat, tomek, adrian, atul, karol, abosh

Differential Revision: https://phab.comm.dev/D4491