* Added a simple lttb aggregate function
* Added support for multiple datatypes
* Added support for Date and Date32, updated LTTBData struct
* Updated code to handle bucket size 0 and 1
* Added sort for LTTBData
* Added tests and documentation
* Added some code style fixes
* Added function to new func ref file
* Removed function from new func ref file
* Apply suggestions from code review
* Updated unit tests
* updated LTTB data code
* Minor style fixes
* Updated code with std sort
* updated tests
* Renamed lttb to largestTriangleThreeBuckets
* Added alias lttb
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Co-authored-by: Alexey Milovidov <milovidov@clickhouse.com>
