container-utils: docker: enrich container meta with container image digest

[mmat11]

Description

Add container image digest to container meta when using docker runtime

Testing done

• Unit tests
• Manual test

before:

"containerMeta":{
    "runtimeName":"docker",
    "containerID":"24878827d73c97435ad1ceee6fc5fc26f402723065e557bb4d1934b61a7fd8ab",
    "containerName":"competent_swanson",
    "containerImageName":"ubuntu:noble-20240429",
    "containerImageDigest":""
}

after:

"containerMeta":{
    "runtimeName":"docker",
    "containerID":"aaeaa9cc31a183c42c6762bb32aef883ecbfb48e4f13320292bfd3ff8cd16d94",
    "containerName":"funny_goldwasser",
    "containerImageName":"ubuntu:noble-20240429",
    "containerImageDigest":"sha256:3f85b7caad41a95462cf5b787d8a04604c8262cdcdf9a472b8c52ef83375fe15"
}

[blanquicet]

Hi @mmat11, thanks for your contribution and welcome to the IG community!

The PR looks good from code inspection but I still need to test it. For now, I'll run the CI. BTW, if you consider the PR is ready, please mark it as ready.