Support signing/verifying image from a private registry using a self-signed certificate

[FeynmanZhou]

Discussed in #1097

^{Originally posted by lmussier December 3, 2024}
Note sure about the title but here is my use case.
We have a registry exposing a self signed certificate and the only way we found to be able to verify the image is to do something like :
export SSL_CERT_FILE=/home/lmussier/source/app-signature/ca.crt
Is there another way of doing this?