Implement mapper caching to reduce GC utilization

[vrogach2020]

Affects #96

[vrogach2020]

Also we must consider serialization code in springdata and provide perfomance

[ArtDu]

@akudiyar thoughts

Raw idea: we should define a "tagging" API for mappers (e.g. a hashcode for the whole stack) that we can use for caching >the other mappers. Using such tag (hashcode) can allow caching mappers without space schema involved, but it will >require each converter and mapper to provide a unique tag (hashcode).