matrix: Update irc-bridge config from config.sample.yaml

roles/matrix/templates/irc-bridge.yaml.j2

@@ -444,6 +444,8 @@ ircService:
     ruleFile: "./provisioning.rules.yaml"
     # Watch the file for changes, and apply the rules. Default: false
     enableReload: true
+    # Number of channels allowed to be bridged
+    roomLimit: 50
 
   # WARNING: The bridge needs to send plaintext passwords to the IRC server, it cannot
   # send a password hash. As a result, passwords (NOT hashes) are stored encrypted in