feat: add config view command

[alessiodionisi]

Related issue(s)

With this PR a new command (kratos config view) to print the current configuration, including the defaults, is introduced. Addresses #3617 issue and #3027 discussion. Can be extended with --output flag to set the format, right now YAML is used. Opened as draft to discuss about it.

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
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  vulnerability. If this pull request addresses a security vulnerability, I
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• I have added tests that prove my fix is effective or that my feature
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