Add Delta Lake to Iceberg Yaml blueprint IT

[derrickaw]

1. Add Delta Lake to Iceberg Yaml blueprint IT
2. Add a new blueprints folder for post commit tests for blueprints. Currently, we have individual transforms tested in precommit and postcommit, but the blueprints we do have are currently mocked examples.
3. Passing run - https://github.com/apache/beam/actions/runs/30488274371

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[github-actions]

Reminder, please take a look at this pr: @claudevdm @Abacn

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[damccorm]

Thanks, the example looks good to me, just had a naming question (also there are pr conflicts)

[damccorm]

Are we overloading the term blueprint here? These aren't the blueprints that are being served as part of Dataflow's job builder, right?

Maybe e2e would be a more appropriate folder name