[services] Lib - Move base reactor
Summary:
Depends on D3909
Moving base reactor from both blob/backup to the mutual "lib" space.
Test Plan:
No real changes are applied, just moving stuff around, so services should still build and that's the test plan
cd services yarn run-blob-service yarn run-backup-service
Reviewers: palys-swm, ashoat
Reviewed By: palys-swm, ashoat
Subscribers: ashoat, palys-swm, Adrian, atul, yayabosh
Differential Revision: https://phabricator.ashoat.com/D3910