Option to project secrets as files

[bryopsida]

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Several security benchmarking tools look for patterns like this.

            - name: "ADMINHASH"
              valueFrom:
                secretKeyRef:
                  name: somename
                  key: adminHash

And mark a finding due to policies such as:

• https://avd.aquasec.com/compliance/kubernetes/cis-kubernetes-benchmarks-v1.23-1.23/5.4.1/
• https://www.tenable.com/policies/cloud-security/AC_K8S_0051
• https://www.tenable.com/audits/items/DISA_STIG_Kubernetes_v1r11.audit:fdb2906c002a74a6f822c62bef0d8ed0

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It would be nice if there was an option/toggle such as.

secretsAsFiles: true

That when enabled removed all usage such as

            - name: "ADMINHASH"
              valueFrom:
                secretKeyRef:
                  name: somename
                  key: adminHash

This would be off/disabled by default to preserve existing behavior and allow users to opt in if they want it.

I'm willing to take on the PR to do this but may need some guidance on the preferred way to wire in the values as files.

From looking at the manifests the following properties would need to be provided through files.

• COUCHDB_ERLANG_COOKIE
• COUCHDB_SECRET
• COUCHDB_PASSWORD
• COUCHDB_USER
• ADMINUSERNAME
• ADMINHASH