Timestamp subtraction and interval operations for ScalarValue (apac…

…he#5603)

* first implementation and tests of timestamp subtraction

* improvement after review

* postgre interval format option

* random tests extended

* corrections after review

* operator check

* flag is removed

* clippy fix

* toml conflict

* minor changes

* deterministic matches

* simplifications (clippy error)

* test format changed

* minor test fix

* Update scalar.rs

* Refactoring and simplifications

* Make ScalarValue support interval comparison

* naming tests

* macro renaming

* renaming macro

* Utilize DateTime<Tz> parsing timezone

* Get rid of boilerplate by using convenience functions

* Get rid of boilerplate by using convenience functions (part 2)

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Co-authored-by: Mehmet Ozan Kabak <[email protected]>