Allow specifying additional path components in archiveCommitArtifacts

[remexre]

Right now, whenever Silver builds a new commit, silver-ableC gets rebuilt too. When it runs melt.archiveCommitArtifacts("jars/*.jar"), this clobbers the previous JARs. The temporary solution I'm thinking of is storing silver-ableC artifacts as https://foundry.remexre.xyz/commit-artifacts/${silver-ableC-commit}/${silver-commit}/*.jar. Thoughts?

Aside: Is there a way to do O_EXCL for the copy?

[krame505]

Oh sorry I overlooked this. That seems like a fine approach.