Cleanup serialization

[ngbrown]

This is a split-off of what was #1425.

This focuses only on the clean up of attributes and overloads. I used some Roslyn Analyzers that I wrote based on:

• CA2229
• CA2235
• CA2239
• CA2240

There are changes to visibility in the public API.

Possible breaking changes:

• Serialization of some exceptions has changed.
• StatefulPersistenceContext and ProxyObjectReference are now sealed.
• De-serialization constructors which were public are now protected. This impacts following classes: Configuration, DuplicateMappingException, ADOConnectionException, ConstraintViolationException, DataException, GenericADOException, LockAcquisitionException, SQLGrammarException, InvalidProxyTypeException.
• Classes marked with Serializable attribute but which were not actually serializable have no more the attribute. This impacts following classes: Mappings, NativeSQLQueryPlan, AbstractEvent and all its descendants, EntityMetamodel, Property and all its descendants.
• ISerializable classes lacking a de-serialization constructor have now one. It should be called by descendant classes own de-serialization constructor. This impacts following classes: CascadeStyle, SqlParseException, DetailedSemanticException, InvalidPathException, SemanticException, QueryExecutionRequestException, ParserException.