Yang Model Ext: Provide utility functions for Schema Context derived tree

Currently there are several instances of logical immutable tree implementation,
which are addressable by YangInstanceIdentifier and are purelly derived from
Schema Context.

Currently existing tree implementations are lazily constructed, and shares lot of tree construction related code, lookup code and differs only in data / metadata stored.

Such examples of these trees are:

SchemaAwareApplyOperation
DataNormalizationOperation

BindingDataCodec - this is special case, since this is physically one tree,
but logically represent two logically differently structured trees:

Tree addressable by binding.InstanceIdentifier and tree addressable by YangInstanceIdentifier.