core: adding RetrieveDataMaxTimeInMinutes config value

This patch introduces RetrieveDataMaxTimeInMinutes config value which
indicates what's the maximum time for 'retrieval' operation.

Change-Id: I5058887601ec210b3bf75f88e98c026d4decf981
Signed-off-by: Liron Aravot <laravot@redhat.com>