Move classes under the same package to avoid internal classes being
exposed to the outside. Remove public visibility outside 3 classes:
EsDriver, EsDataSource and EsTypes.
The driver only has one package, namely org.elasticsearch.xpack.sql.jdbc
Use Es prefix for classes to ease name conflict and indicate their
destination
Fix#35437
Make SQL aware of missing and/or unmapped fields treating them as NULL
Make _all_ functions and operators null-safe aware, including when used
in filtering or sorting contexts
Add missing and null-safe doc value extractor
Modify dataset to have null fields spread around (in groups of 10)
Enforce missing last and unmapped_type inside sorting
Consolidate Predicate templating and declaration
Add support for Like/RLike in scripting
Generalize NULLS LAST/FIRST
Introduce early schema declaration for CSV spec tests: to keep the doc
snippets in place (introduce schema:: prefix for declaration)
upfront.
Fix#32079
Costin Leau
Jason Tedor
Thiago Souza
Kazuhiro Sera
Costin Leau
Andrei Stefan
Lisa Cawley