Use datum arithmetic scalar value (#7375)

* Use Datum arithmetic for ScalarValue

* Improve comments

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Co-authored-by: Andrew Lamb <[email protected]>

Author: tustvold

datafusion/common/src/delta.rs

@@ -19,7 +19,6 @@ pub mod alias;
 pub mod cast;
 mod column;
 pub mod config;
-pub mod delta;
 mod dfschema;
 pub mod display;
 mod error;