feat : support spark compatible int to timestamp cast (#20555)

## Which issue does this PR close?

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- Closes #20554 

Ref : #20555

## Rationale for this change

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## What changes are included in this PR?

1. Created a new cast scalar UDF to support int to timestamp casts
(spark compatible). The goal is to leverage this is as an entry point
for all spark compatible / df incompatible casts
 
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## Are these changes tested?

1. Yes (through series of unit tests testing various edge cases like
overflow , null input etc)

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## Are there any user-facing changes?

1. Yes. We are bringing in ability to leverage spark compatible cast
operations in DF through `spark_cast` as a first step. Next step would
be to make changes to the planner to leverage spark compatible cast
instead of regular cast operations

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Author: coderfender