Add --sync-files flag while synchronzing

[samirsilwal]

Changes

• Add --sync-files flag to synchronize command
• It is list of objects that is to be synchronized
• This introduces an explicit way of providing only the specific object to be synced
• The path should be list of relative paths to base path given in sync-db yaml
• When there is non empty sync files provided, teardown process in synchronize is skipped and we simply update the objects