Test : Enable s390x support for runtime datascience 3.11/3.12

[Nash-123]

Summary

This PR introduces s390x (IBM Z) support and build optimizations for the runtime-datascience notebook images for Python 3.11 and 3.12.

• Reduced build time for s390x: ~2–2.3 hours (down from 4 hours on building natively)
• No impact on other platforms (x86_64, arm64, etc.)
• Elyra-compatible: validated for notebook execution

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Key Changes

Dockerfile.cpu (Python 3.11 & 3.12)

• Introduced ARG TARGETARCH for architecture-specific builds
• Multi-stage build using s390x-builder to build pyarrow from source on IBM Z
• Enabled cache mounts option for dnf and pip
• Optimizations for s390x:
  • Installs Rust & Cargo
  • Uses compiler flags (CFLAGS="-O3")
  • Installs development dependencies required for pyarrow compilation
• Package installation and build logic gated via TARGETARCH

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Pipfile (Python 3.11 & 3.12)

Architecture-specific markers added to exclude incompatible packages on s390x:

codeflare-sdk = { version = "~=0.30.0", markers = "platform_machine != 's390x'" }
py-spy        = { version = "~=0.4.0", markers = "platform_machine != 's390x'" }
ray           = { version = "~=2.47.1", markers = "platform_machine != 's390x'", extras = ["data", "default"] }
pyarrow       = { version = "~=21.0.0", markers = "platform_machine != 's390x'" }

Regenerated Pipfile.locks using Renewal Action

Image seems to be building fine on Konflux:

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[wznoinsk]

the s390x, x86 and arm konflux builds succeeded, the ppc64 failed:
https://konflux-ui.apps.stone-prd-rh01.pg1f.p1.openshiftapps.com/ns/rhoai-tenant/applications/external-rhoai-v2-23-multi-arch-poc/pipelineruns/odh-pipeline-runtime-ds-cpu-py311-ubi9-n-v2-23-multi-arch-ss6q6/logs?task=build-images

this code is good for s390x, it's ok to merge this code to the main branch and continue working on ppc64 in a separate pull request - or add ppc64 support to this one - up to you

[Nash-123]

• Build Notebooks (pr) / build (runtime-datascience-ubi9-python-3.11, 3.11, linux/s390x, false) / build (pull_request)

Hi @wznoinsk, Sure. Thanks!! . We've raised the PR for this on the upstream :- opendatahub-io#1513 . currently working with @jiridanek @atheo89 to get it merged

Once that gets merged upstream, the changes should sync downstream, and I believe we’ll be good on the s390x front.

Regarding the ppc64 arch, @npanpaliya. would you like to add here anything ?

[npanpaliya]

@Nash-123 - We will add Power support in a separate PR. Earlier we had created a separate dockerfile but as per the latest discussion, we need to put back our changes in the same Dockerfile, which may take time. So, don't want to hold off your PR for that. @AaruniAggarwal will raise a new PR.

[Nash-123]

@Nash-123 - We will add Power support in a separate PR. Earlier we had created a separate dockerfile but as per the latest discussion, we need to put back our changes in the same Dockerfile, which may take time. So, don't want to hold off your PR for that. @AaruniAggarwal will raise a new PR.

Sure, Sounds good. Thanks @npanpaliya !!
fyi: @wznoinsk