[Feature] Iceberg Custom base_location

[chg-dbt-lprocopi]

Is this your first time submitting a feature request?

• I have read the expectations for open source contributors
• I have searched the existing issues, and I could not find an existing issue for this feature
• I am requesting a straightforward extension of existing dbt-snowflake functionality, rather than a Big Idea better suited to a discussion

Describe the feature

Allow users to overwrite the default base_location. Not just add a base_location_subpath

Describe alternatives you've considered

No response

Who will this benefit?

Teams using dbt Snowflake Iceberg models who need to change the storage location in S3

Are you interested in contributing this feature?

Happy to!

Anything else?

Docs on current configuration: https://docs.getdbt.com/reference/resource-configs/snowflake-configs#base-location-subpath