Memory Quota: annotated values should keep track of key size

Currently values only keep track of the document size.
We could implement an ad hoc annotatedValue.Size(), which returns the value size plus the key size, which would report a more realistic memory footprint where the key is larger than the value.

I have checked all the instances of annotated.SetId() and we would not be double counting key sizes, and by just amending Size(), we would automatically correct the whole of memory tracking for annotated values.