support additional digest algorithms and the RFC-8954 nonce extension for custom OCSP URL validation

[emattheis]

The OCSP validation support in KeyStore explorer allows one to specify a custom responder URL for performing the OCSP check, but doesn't not support any further customization. In particular, OCSP requests are made using the SHA-1 digest algorithm and do not include the nonce extension. I would like to see KeyStore Explorer offer the ability to use the SHA-256, SHA-384, or SHA-512 algorithms and include the nonce extension in the request.

I have implemented this feature and will be submitting a PR shortly.

[kaikramer]

Thank you, that's a very useful improvement fror KSE! Much appreciated