Support for encrypted inline file content

[soubinan]

Feature Request

Environment

I use ignition for coreos on bare metal and KVM / XEN virtual machines powered by XCPng and Cloudstack private cloud

Desired Feature

It would be great to be able to encypt an inline file content for file with credentals configuration for example (the same we are doing on users passwords but for file content

Example of what it could looks like:

...
storage:
  disks:
    ...
  directories:
    ...
  files:
    - path: /etc/my_app/my_app.conf
      mode: 0400
      contents:
        inline: |
          algo-$y$j9T$GHWl3yQUIHdkwYhEk8R8J.$cYf8nRRKA92jvQBtxnPmKYmihvzTXRW5B6ETCCXKPI2
        ...
...