Naive convert timezone func, with some date_add bug fixes (#143)

* Test

* Add least, greatest and mock for dateadd

* logic part if we're to continue using utf8, tested with this query with curl "select dateadd('\''days'\'', 3,'\''2024-12-26'\'')"

* snowflake compatability

* changed unwrap's for unwrap_or's per Scott's advice, question do we go the ZII pattern from Casey Muratori (MollyRocket) meaning the defaults or do we want some specific panic?

* Fix map_or

* Fix map_or

* Fix map_or

* fixed date_add possible overflow, leap years and months

* dateadd completed

* Fix schema

* mock convert timezone and datediff

* forgot

* bandai fix for snowflake macro generator in dateadd

* rotate query preprocess

* working on "convert_timezone" func

* small fix

* working on convert_timezone logic with chrono tz

* strange bug in datafusion?

* almost working

* patched strange bug with datafusion

* one feature and one bug left

* added snowlfake local tz feature

* pattern matching for udfs

* math is not right

* fixed math

* blocked, timestamps are broken in signtures also

* comment

* no tz in utf8 version

* 'correct' solution for now

* merging changes fix

* merging conflicts fix

* clippy fix

* clippy fix

* clippyyyyyy

* added tests, removed dead code

* cargo fmt

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Co-authored-by: osipovartem <[email protected]>

Author: DanCodedThis