PSMDB-1690 adjust regression tests for bazel builds

[olexandr-havryliak]

No description provided.

[Copilot]

Pull Request Overview

This PR adjusts the PSMDB regression test Jenkins pipeline to support bazel builds alongside the existing scons builds. The changes add build platform selection and modernize the Docker build process by installing buildx plugin.

• Adds a new build platform parameter to choose between bazel and scons
• Removes scons-specific parameters and logic for storage engine configurations
• Modernizes Docker builds by installing buildx plugin and using DOCKER_BUILDKIT

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