feat: Added support for templates in external secrets

[Ash-exp]

Description

Add support for templates in external secrets

Fixes https://github.com/devtron-labs/sprint-tasks/issues/934, #5861, #5321

New ESO support from future reference charts
deployment.yaml

{{if (or (eq .externalType "ESO_GoogleSecretsManager") (eq .externalType "ESO_AWSSecretsManager") (eq .externalType "ESO_HashiCorpVault") (eq .externalType "ESO_AzureSecretsManager"))}}
          {{- if and (.esoSubPath) (ne (len .esoSubPath) 0) }}
          {{- range .esoSubPath }}
            - name: {{ $cmName | replace "." "-"}}-vol
              mountPath: {{ $cmMountPath}}/{{ . }}
              subPath: {{ . }}  
          {{- end }}
          {{- else }}
          {{- range .esoSecretData.esoData }}
            - name: {{ $cmName | replace "." "-"}}-vol
              mountPath: {{ $cmMountPath}}/{{ .secretKey }}
              subPath: {{ .secretKey }}  
          {{- end }}
          {{- end }}
          {{- else }}             
          {{- range $k, $v := .data }}
            - name: {{ $cmName | replace "." "-"}}-vol
              mountPath: {{ $cmMountPath}}/{{ $k}}
              subPath: {{ $k}}
          {{- end }}
          {{- end }}

externalsecrets.yaml

  target:
    name: {{ .name}}
    creationPolicy: Owner
    {{- if .esoSecretData.template }}
    template:
      {{- toYaml .esoSecretData.template | nindent 6 }}
    {{- end }}
  {{- if .esoSecretData.esoDataFrom }}
  dataFrom:
    {{- toYaml .esoSecretData.esoDataFrom | nindent 4 }}
  {{- else }}
  data:
  {{- range .esoSecretData.esoData }}
  - secretKey: {{ .secretKey }}
    remoteRef:
        key: {{ .key }}
        {{- if .property }}
        property: {{ .property }}
        {{- end }}
  {{- end}}
  {{- end}}

Checklist:

• The title of the PR states what changed and the related issues number (used for the release note).
• Does this PR requires documentation updates?
• I've updated documentation as required by this PR.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have tested it for all user roles.
• I have added all the required unit/api test cases.

Does this PR introduce a user-facing change?

[gitguardian]

⚠️ GitGuardian has uncovered 2 secrets following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secrets in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
10220829	Triggered	Generic High Entropy Secret	fb7b4fa	charts/devtron/devtron-bom.yaml	View secret
10220829	Triggered	Generic High Entropy Secret	fb7b4fa	charts/devtron/values.yaml	View secret

🛠 Guidelines to remediate hardcoded secrets

1. Understand the implications of revoking this secret by investigating where it is used in your code.
2. Replace and store your secrets safely. Learn here the best practices.
3. Revoke and rotate these secrets.
4. If possible, rewrite git history. Rewriting git history is not a trivial act. You might completely break other contributing developers' workflow and you risk accidentally deleting legitimate data.

To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

---

^{🦉 GitGuardian detects secrets in your source code to help developers and security teams secure the modern development process. You are seeing this because you or someone else with access to this repository has authorized GitGuardian to scan your pull request.}

[sonarcloud]

Quality Gate failed

Failed conditions
C Security Rating on New Code (required ≥ A)

See analysis details on SonarCloud

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