Dockerfile: Inject merge_syft_sbom script to /usr/local/bin

[eskultety]

When commit 49ba69d0 converted the image build to multi-stage it forgot to install the merge_syft_sbom.py utility script that was previously installed as part of copying the whole repo into the image to /src/utils/merge_syft_sbom.py. This patch takes a bit of a different path by installing the script as a utility binary to a more standardized location.

Fixes: 49ba69d0de05addbca966b683f75f8a71fcbd1c1 Resolves: https://github.com/containerbuildsystem/cachi2/issues/582

Maintainers will complete the following section

• [ ] Commit messages are descriptive enough
• [ ] Code coverage from testing does not decrease and new code is covered
• [ ] Docs updated (if applicable)
• [ ] Docs links in the code are still valid (if docs were updated)

Note: if the contribution is external (not from an organization member), the CI pipeline will not run automatically. After verifying that the CI is safe to run:

• approve GitHub Actions workflows by clicking a button
• approve the Red Hat Trusted App Pipeline container build by commenting /ok-to-test (as is the standard for Pipelines as Code)

[chmeliik]

This patch takes a bit of a different path by installing the script as a utility binary to a more standardized location.

This will also need a corresponding update in konflux-ci/build-definitions (in the same PR that will update to cachi2 0.9.1)

[eskultety]

This patch takes a bit of a different path by installing the script as a utility binary to a more standardized location.

This will also need a corresponding update in konflux-ci/build-definitions (in the same PR that will update to cachi2 0.9.1)

Yep, will take care of that in that PR.