Add CA info to mirage and eiti

[dlapiduz]

@konklone Something like this?

[konklone]

Yes, this will do. If you come across the original filenames of the intermediate certs you were given (for example, our Namecheap/Comodo ones are COMODORSAAddTrustCA.crt and COMODORSADomainValidationSecureServerCA.crt), adding them to the README would be helpful.

[konklone]

Thanks, @dlapiduz!