Make QueryContext partially go through kernel API

o Replace prior LabelResolution
o Support for resolving property keys at plan build time
o Make properties use propertyKeyId
o Make Cypher delete entity operations go through kernel
o Introduce TokenContext has a shared trait of {Plan,Query}Context
o Enhance TokenType and KeyToken to provide getId, getOptId, getOrCreateId functionality
o Make CloseableIterator always return Maps and materialize Streams