Set cosign verify 'offline' for os-image-info

What does this MR do and why?

While working on #3198 (closed), I couldn't identify any obvious reason why the job took more than 10 minutes. Since the cosign verify command, by default attempts to reach the internet for some checks. I think network or proxy issues could cause the job to fail.

To address this, we can disable the online checks and only verify the signature offline (we only need that).

Additionally, I noticed that the following issue was raised during each cosign verify execution:

failed to create TUF client failed to create initial TUF updater: mkdir /.sigstore: permission denied

I fixed this issue by configuring .sigstore to be stored in the /tmp directory of the kube-job.

Related reference(s)

#3198 (closed)

Test coverage

CI configuration

Below you can choose test deployment variants to run in this MR's CI.

Click to open to CI configuration

Legend:

Icon	Meaning	Available values
☁️	Infra Provider	capd, capo, capm3
🚀	Bootstrap Provider	kubeadm (alias kadm), rke2, okd, ck8s
🐧	Node OS	ubuntu, suse, na, leapmicro
🛠️	Deployment Options	light-deploy, dev-sources, ha, misc, maxsurge-0, logging, no-logging, cilium
🎬	Pipeline Scenarios	Available scenario list and description
🟢	Enabled units	Any available units name, by default apply to management and workload cluster. Can be prefixed by mgmt: or wkld: to be applied only to a specific cluster type

• 🎬 preview ☁️ capd 🚀 kadm 🐧 ubuntu

• 🎬 preview ☁️ capo 🚀 rke2 🐧 suse

• 🎬 preview ☁️ capm3 🚀 rke2 🐧 ubuntu

• ☁️ capd 🚀 kadm 🛠️ light-deploy 🐧 ubuntu

• ☁️ capd 🚀 rke2 🛠️ light-deploy 🐧 suse

• ☁️ capo 🚀 rke2 🐧 suse

• ☁️ capo 🚀 rke2 🐧 leapmicro

• ☁️ capo 🚀 kadm 🐧 ubuntu

• ☁️ capo 🚀 kadm 🐧 ubuntu 🟢 neuvector,mgmt:harbor

• ☁️ capo 🚀 rke2 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capo 🚀 kadm 🎬 wkld-k8s-upgrade 🐧 ubuntu

• ☁️ capo 🚀 rke2 🎬 rolling-update-no-wkld 🛠️ ha 🐧 suse

• ☁️ capo 🚀 rke2 🎬 sylva-upgrade-from-1.5.x 🛠️ ha 🐧 ubuntu

• ☁️ capo 🚀 rke2 🎬 sylva-upgrade-from-1.5.x 🛠️ ha,misc 🐧 ubuntu

• ☁️ capo 🚀 rke2 🛠️ ha,misc 🐧 ubuntu

• ☁️ capo 🚀 rke2 🛠️ ha,misc,openbao🐧 suse

• ☁️ capo 🚀 rke2 🐧 suse 🎬 upgrade-from-prev-tag

• ☁️ capm3 🚀 rke2 🐧 suse

• ☁️ capm3 🚀 kadm 🐧 ubuntu

• ☁️ capm3 🚀 ck8s 🐧 ubuntu

• ☁️ capm3 🚀 kadm 🎬 rolling-update-no-wkld 🛠️ ha,misc 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🎬 wkld-k8s-upgrade 🛠️ ha 🐧 suse

• ☁️ capm3 🚀 kadm 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capm3 🚀 rke2 🎬 sylva-upgrade-from-1.5.x 🛠️ ha 🐧 suse

• ☁️ capm3 🚀 rke2 🛠️ misc,ha 🐧 suse

• ☁️ capm3 🚀 rke2 🎬 sylva-upgrade-from-1.5.x 🛠️ ha,misc 🐧 suse

• ☁️ capm3 🚀 kadm 🎬 rolling-update 🛠️ ha 🐧 suse

• ☁️ capm3 🚀 ck8s 🎬 rolling-update 🛠️ ha 🐧 ubuntu

• ☁️ capm3 🚀 rke2|okd 🎬 no-update 🐧 ubuntu|na

• ☁️ capm3 🚀 rke2 🐧 suse 🎬 upgrade-from-release-1.5

• ☁️ capm3 🚀 rke2 🐧 suse 🎬 upgrade-to-main

Global config for deployment pipelines

• autorun pipelines
• allow failure on pipelines
• record sylvactl events

Notes:

• Enabling autorun will make deployment pipelines to be run automatically without human interaction
• Disabling allow failure will make deployment pipelines mandatory for pipeline success.
• if both autorun and allow failure are disabled, deployment pipelines will need manual triggering but will be blocking the pipeline

Be aware: after configuration change, pipeline is not triggered automatically. Please run it manually (by clicking the run pipeline button in Pipelines tab) or push new code.