[services] Move folly from Blob to Backup base

Summary:
As we'll need to use folly for the dev mode in the backup as well, I decided to move folly installation from the blob base image to the backup base image

Depends on D3179

Test Plan:
Remove backup-base, backup-server, blob-base and blob-server as well as all caches and rebuild the images:

cd services
yarn build-backup-base
yarn build-blob-base
yarn run-blob-service
yarn run-backup-service

services should work as they did before this change.

Reviewers: palys-swm, geekbrother, varun, jimpo, ashoat

Reviewed By: jimpo, ashoat

Subscribers: benschac, jimpo, ashoat, palys-swm, Adrian, atul

Differential Revision: https://phabricator.ashoat.com/D3198