Need crypto.createVerify for Cognito RS256 JWT token validation

[kennu]

AWS Cognito uses RS256 for JWT tokens. This format is supported e.g. by API Gateway HTTP JWT Authorizers. To verify those JWT tokens in our own code, we would need crypto.createVerify RSA-SHA256 support in LLRT.

Even nicer would be for jsonwebtoken to work out-of-the-box in LLRT, but I believe crypto.createVerify is the minimum required functionality.

[richarddavison]

This is prioritized! We'll add it so stay tuned. Also mentioned here:
#184

[richarddavison]

Closing as being tracked by #184