Adding buildscript and Dockerfile for agentstackv0.4.3

[Simran-Sirsat]

Checklist

• Have you checked and followed all the points mention in the CONTRIBUTING.MD
• Have you validated script on UBI 9 container
• Did you run the script(s) on fresh container with set -e option enabled and observe success ?
• Did you have Legal approvals for patch files ?

[github-actions]

@Simran-Sirsat

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