DATAMONGO-870 - Added support for sliced query execution.

Added support for Slice as return type for query methods. The execution will expand the requested page size by one to read one more element than actually requested. If that additional element is returned, it will considered to be an indicator for whether a next slice is available.

Related issues: DATACMNS-397.
DATAMONGO-871 - Add support for arrays as query method return types.

Changed AbstractMongoQuery to potentially convert all query execution results using the DefaultConversionService in case the query result doesn't match the expected return value.

This allows arrays to be returned for collection queries as the conversion service cam transparently convert between collections and arrays.