Usage:
//Load the platform JWKS public keys from a url
GuavaCachedSignatureKeyProvider platformKeys = new GuavaCachedSignatureKeyProvider(
new URLJWKSKeyProvider(new URL("https://fancylms.org/.well-known/jwks.json")));
//Transform an HttpServletRequest into an LTI13Request
LTI13Request ltiRequest = LTI13JWSParser.convertOrThrow(platformKeys, request);