Implement safe_cast macro

[adamtwo]

Describe the feature

Currently,dbt-teradata-utils doesn't implement safe_cast macro. As a result, dbt-utils defaults to the standard cast(var as type) syntax. Teradata supports trycast which doesn't error out when the cast cannot be done. dbt-teradata-utils should have an implementation of safe_cast that uses trycast.

Describe alternatives you've considered

Continue with the current non-safe implementation.

Additional context

See https://github.com/dbt-labs/dbt-utils/blob/main/macros/cross_db_utils/safe_cast.sql

Who will this benefit?

safe_cast is useful when we can't be certain about data types and formats.

Are you interested in contributing this feature?