Add encrypt image and decrypt image actions (backport #1165)

[mergify]

Summary

From previous PR comment : #1151 (review)

Modify

• show image_ns/image_displayName as encrypt / decryt dropdown options
• add Encrypt Image / decrypt Image actions
• show Source Image in image detail and fix source Image in edit view page

PR Checklist

• Is this a multi-tenancy feature/bug?
  • Yes, the relevant RBAC changes are at:
• Do we need to backport changes to the old Rancher UI, such as RKE1?
  • Yes, the relevant PR is at:
• Are backend engineers aware of UI changes?
  • Yes, the backend owner is: @Yu-Jack

Related Issue #
harvester/harvester#6493

Occurred changes and/or fixed issues

Technical notes summary

Areas or cases that should be tested

Areas which could experience regressions

Screenshot/Video

Add Encrypt Image or Decrypt Image actions

Show source Image in detail page

Show image namespace + displayName as options

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This is an automatic backport of pull request #1165 done by [Mergify](https://mergify.com).