remove all messageapi code from package, moved to its own package, will be integrated when that package is complete

moved some RecordUtils and RelationshipUtils methods back to ContainerUtils, not enough methods to justify separate static classes

FieldUnit, RootUnit, and RelationshipUnit which all form a single
ContainerRecord. This makes it clear what the internal topology considers
a record - only user facing records (SchemaRecords) are considered records.
Containers are explicitly made into the intermediate translation containment
system between protocol (system) and schema (user).

updated SimpleRelationship and BaseRelationship - pulled parent, child, field out of BaseRelationship, this lives in SimpleRelationship, as there may be other types of relationships than joins

matching the rest of the package structure. update SessionSpec to match.

reorganize Utils packages, change RecordUtils to SchemaUtils, move ConditionUtils and FieldUtils to schema namespace.
this makes the Request imports more clear

update all container related code to match new structural changes to model, incorporating split metadata, new container spec, and added relationship type

modified container configuration, separated out metadata/container specs, added relationships spec, simplified containers spec pattern

changed default to use SimpleContainer, added copy constructor for SimpleContainer/BaseContainer, added ContainerUtils class