Add new decoder for multiline decoding

[ViToRiO92]

Depending on the loadbalancer you need to decode the certificate in the header. there are currently three decoder with the setting "x_forwarded_for_client_cert_header_decoders". if you want to use Citrix Netscaler you are getting a certificate forwarded in the header that is a single line. it is not possible to rewrite the header in Citrix Netscaler.

I would like to request a ne decoder to convert a singleline to multiline.

[vercel]

@ViToRiO92 is attempting to deploy a commit to the HashiCorp Team on Vercel.

A member of the Team first needs to authorize it.

[hashicorp-cla-app]

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[hashicorp-cla-app]

Thank you for your submission! We require that all contributors sign our Contributor License Agreement ("CLA") before we can accept the contribution. Read and sign the agreement

Learn more about why HashiCorp requires a CLA and what the CLA includes

_{Have you signed the CLA already but the status is still pending? Recheck it.}

[heatherezell]

Hi there! Please sign the CLA, and once that's done I'll get this sent for our engineers to review. Thanks!

[ViToRiO92]

Hi there! Please sign the CLA, and once that's done I'll get this sent for our engineers to review. Thanks!

Hi, i signed the CLA. I hope it will update the status soon.