Experimental: Hydrate models from raw BSON

[GromNaN]

Q	A
Type	improvement
BC Break	yes
Fixed issues	-

Summary

Work with BSON Document and Array in order to improve memory usage

• Deprecate using PreLoadEventArgs::getData(), we may create a new class that wraps MongoDB\BSON\Document to enable updating some documents only. Or use MongoDB\Model\Document.
• The default typeMap of the client is not modified. We set the typeMap to BSON only when the result is going to be hydrated.
• Breaking change:

Todo:

• Run benchmarks