Import selected PRs from SingularityCE 4.1.x

[DrDaveD]

Add --authfile option:

• OCI credentials storage: only store "auth" field sylabs/singularity#2227
• add --authfile to OCI login/logout, pull, push, and action-cmds sylabs/singularity#2225
• clear up relationship btw --authfile facility & DOCKER_xyz env vars sylabs/singularity#2236
• build: add support for --authfile flag sylabs/singularity#2238

Refactor to use go-container registry:

• refactor: minimise containers/image imports sylabs/singularity#2376
• refactor: containers/image -> ggcr step 2  sylabs/singularity#2379
• Re-implement bars when fetching remote OCI images via ggcr sylabs/singularity#2407
• refactor: use ggcr for e2e OCI image copy sylabs/singularity#2390

Miscellaneous:

• e2e: move aside existing remote.yaml files in remoteUseExclusive() sylabs/singularity#2230
• (not needed) buildkit: drop otel sylabs/singularity#2329
• document e2e helpers, best practices, etc. sylabs/singularity#2374
• update node ver. in CircleCI: 18 -> 20 sylabs/singularity#2380
• fix: Execute correct %appscript and add test for instance start --app sylabs/singularity#2408
• (not needed) Consider the host cleanup commit from fuse: automatically use squashfuse for images, deprecate --sif-fuse sylabs/singularity#2451

Fixes backported to 4.1 branch:

• cgroups: rework checks for cgroup support sylabs/singularity#2569
• (not needed) engine: cleanup host directly on StageOne failure sylabs/singularity#2573
• (not needed) fix: Address layer / image extraction issues in user namespaces sylabs/singularity#2699
• fix: store docker.io credential like index.docker.io sylabs/singularity#2777

Lint:

• (not needed) linter fixes for golangci-lint 1.55.1 sylabs/singularity#2281
• chore: address context-related FIXMEs sylabs/singularity#2373
• Address further FIXMEs sylabs/singularity#2409

[DrDaveD]

@JasonYangShadow why don't you figure on working on the first two batches having to do with --authfile and the go-containerregistry refactor and I'll figure on doing at least some of the miscellaneous. We'll see how things go after those are done.

[JasonYangShadow]

@JasonYangShadow why don't you figure on working on the first two batches having to do with --authfile and the go-containerregistry refactor and I'll figure on doing at least some of the miscellaneous. We'll see how things go after those are done.

Sure, no problem!

[DrDaveD]

@JasonYangShadow great job on finishing the first two batches. Please move on next to the backported fixes. I should to be able to start to do some of the miscellaneous ones next week.