Specialization for Sandwich/Sandwich::Part #2
Description
Currently SandwichDB<SandwichDB<T, BasePrefix>::Part, Prefix>::Part does prefix addition twice on each layer.
We need to introduce specialization for this case that will make Part with a fused prefixes and pass through down to first non-sandwich collection.
Hint: We may create a traits that defines aspect of Part creation and length of its prefix. Network-order/lexicographical increment over prefix might pose a challenge.