Support multi-arch builds in docker setup

Refer [https://github.com/apache/hudi/issues/4985]

Essentially, our current docker demo runs for linux/amd64 platform but not for arm64. We should support multi-arch builds in a fully automated manner. Ideal would be to simply accept a parameter in setup script:
{code:java}
docker/setup_demo.sh --platform linux/arm64
{code}

## JIRA info

- Link: https://issues.apache.org/jira/browse/HUDI-3601
- Type: Epic

Start with docker/setup_demo.sh and read the referenced apache/hudi#4985 issue for context on the existing platform limitation. Trace how the demo currently builds for linux/amd64, then define automated support for a selectable linux/arm64 platform. Done means the setup script accepts the proposed --platform parameter and the Docker demo builds on both architectures.

Written by the indexing model from the issue text.