Bug 16044: Add deep cloning

Bug 16044: Add deep cloning

To avoid the cache to be modified unfortunately, the default behavior of
get_from_cache will be to deep copy if we are getting a structure.
If the item is a scalar, it's simply returned.

Signed-off-by: Jesse Weaver <jweaver@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit 2e0af6e6df279aa08603e9696d35fc7def7bd7d3)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>