Docs - Add bucketing documentation for iceberg

[nicor88]

Is this your first time submitting an issue in dbt-athena?

• I have searched the existing issues, and I could not find an existing issue for this feature

Describe your request/question

Currently Athena docs for bucketing in Iceberg are not really clear, neither dbt-athena docs.
Provide a section about bucketing in:

• dbt-athena readme
• dbt athena docs

Anything else?

No response

[amychen1776]

@nicor88 we want to move away from putting all of this documentation in the readme and now point users to the docs site. Curious what is the exact context that's missing?

[nicor88]

@amychen1776 we need a section with real examples on how to use iceberg bucketing in athena. There is a mismatch between how a athena iceberg bucketing function is called and iceberg canonical function, that leads to ambiguity.

[amychen1776]

Transferring this issue to our docs site since we are not writing documentation in this readme now