Adds arch switch for linux for container runtime support

[iamkirkbater]

When attempting to use backplane-tools within ocm-container on an arm Macbook it would throw an error about not being able to find a lib-x86_64.so file when trying to validate the aws install because of the hardcoded architecture.

This puts the architecture selection within a switch inside of the OS switch statement in order to be able to install the correct arm binary within linux.

This should also help support any future arm-based linux builds, not just ocm-container on macs.

[openshift-ci[bot]]

@iamkirkbater: all tests passed!

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[tnierman]

/lgtm /approve

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: iamkirkbater, tnierman

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/openshift/backplane-tools/blob/main/OWNERS)~~ [tnierman] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment