* SQL: Rename SQL data type DATE to DATETIME
SQL data type DATE has only the date part (e.g.: 2019-01-14)
without any time information. Previously the SQL type DATE was
referring to the ES DATE which contains also the time part along
with TZ information. To conform with SQL data types the data type
`DATE` is renamed to `DATETIME`, since it includes also the time,
as a new runtime SQL `DATE` data type will be introduced down the road,
which only contains the date part and meets the SQL standard.
Closes: #36440
* Address comments
* Added Limitations page
* Made the aggregations page follow the common template for functions
* Modified all tables to have the first row's cells content centered
* Polishing in other various sections
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
