OF-3327: Decouple occupant-ID hashing from the SASL/SCRAM implementation

Do not import `ScramSha1SaslServer` purely to reuse `HMAC_ALGORITHM_NAME` for an internal, authentication-unrelated hash (XEP-0421 occupant IDs). This ties a MUC-layer feature to a SASL-mechanism-specific constant, creating a somewhat awkward muc → sasl dependency for a value that has no conceptual relation to SCRAM authentication.

Author: guusdk

xmppserver/src/main/java/org/jivesoftware/openfire/muc/MUCRoom.java

@@ -4204,9 +4204,9 @@ public String generateOccupantId(@Nonnull final JID userJid)
 
         try {
             // Keep the room's identifier with they key, rather than with the data, which should have slightly improved security properties.
-            final byte[] roomKey = ScramUtils.computeHmac(siteKey.getBytes(StandardCharsets.UTF_8), this.getJID().toBareJID(), ScramSha1SaslServer.HMAC_ALGORITHM_NAME);
+            final byte[] roomKey = ScramUtils.computeHmac(siteKey.getBytes(StandardCharsets.UTF_8), this.getJID().toBareJID(), "HmacSHA1");
 
-            return StringUtils.encodeHex(ScramUtils.computeHmac(roomKey, userJid.toBareJID(), ScramSha1SaslServer.HMAC_ALGORITHM_NAME));
+            return StringUtils.encodeHex(ScramUtils.computeHmac(roomKey, userJid.toBareJID(), "HmacSHA1"));
         } catch (SaslException e) {
             throw new RuntimeException("Unable to compute HMAC for user '" + userJid + "' in room '" + this.getJID() + "' while generating an Occupant ID.");
         }