CyberArk(helm): add cyberark-disco-agent Helm chart, build scripts, and E2E test

- introduce cyberark-disco-agent Helm chart with templates, docs, schema, and values
- add build and release Makefile modules for ark agent and chart publishing
- implement E2E test script for agent deployment and verification
- update main.go for ark agent entrypoint
- integrate chart build and test targets into main Makefiles
- Add image.digest field to values.yaml, schema, and documentation
- Update deployment.yaml to use image digest if provided
- Pass digest in e2e test and chart upgrade scripts
- Output digest variables in release Makefile targets
- Add values.linter.exceptions file for chart validation
- Add ark-verify target to Makefile for chart verification

Signed-off-by: Richard Wall <richard.wall@cyberark.com>

Author: wallrj-cyberark

cmd/ark/main.go

@@ -0,0 +1,7 @@
+package main
+
+import "github.com/jetstack/preflight/cmd"
+
+func main() {
+	cmd.Execute()
+}

deploy/charts/cyberark-disco-agent/.helmignore

@@ -0,0 +1,23 @@
+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+# Common VCS dirs
+.git/
+.gitignore
+.bzr/
+.bzrignore
+.hg/
+.hgignore
+.svn/
+# Common backup files
+*.swp
+*.bak
+*.tmp
+*.orig
+*~
+# Various IDEs
+.project
+.idea/
+*.tmproj
+.vscode/

deploy/charts/cyberark-disco-agent/Chart.yaml

@@ -0,0 +1,18 @@
+apiVersion: v2
+name: cyberark-disco-agent
+description: |-
+  The cyberark-disco-agent connects your Kubernetes or Openshift cluster to CyberArk Discovery and Context.
+
+maintainers:
+  - name: CyberArk
+    email: support@cyberark.com
+    url: https://cyberark.com
+
+sources:
+  - https://github.com/jetstack/jetstack-secure
+
+# These versions are meant to be overridden by `make helm-chart`. No `v` prefix
+# for the `version` because Helm doesn't support auto-determining the latest
+# version for OCI Helm charts that use a `v` prefix.
+version: 0.0.0
+appVersion: "v0.0.0"