GHSA-92HR-GMR6-H8CP Etherpad addressed weak token RNG, login timing, plugin path handling, API request handling

Fix: PR 7906 ether/etherpad. A set of medium/low hardening fixes: - Weak RNG for tokens CWE-330: author/session/readonly IDs were generated with Math.random client and server. Now use crypto.getRandomValues. - Login timing / no failure delay CWE-208/CWE-307: the OIDC interaction login used a...