Enable stateless reset token key rotation

[anrossi]

The stateless reset token key is used for the lifetime of the MsQuic server process. It would be better security hygiene if the stateless reset token key were rotated on an interval (hourly?). One complication with this is it forces all connections active on the server to need a new CID with the new stateless reset token key. One potential design could encode which stateless reset token key to use in a given CID and then generate the stateless reset token key from a base key and the identifying number in the CID. Either with iterations of a hash function over the base key, or concatenation.