When using the configured provider JWT Verifier, it makes
sense to use the provider `CreateSessionStateFromBearerToken`
method. For any extra JWT Issuers, they should use a generic
default verifier.
Have it take in a cipher init function as an argument.
Remove the confusing `newCipher` method that matched legacy behavior
and returns a Base64Cipher(CFBCipher) -- instead explicitly ask for
that in the uses.
All Encrypt/Decrypt Cipher implementations will now take
and return []byte to set up usage in future binary compatible
encoding schemes to fix issues with bloat encrypting to strings
(which requires base64ing adding 33% size)
