[SYS] Multiple connections management (#1947)

Enable the management of different connections at runtime with a set of certs for each.
Add parameters to the WiFi Manager onboarding, client certificates, and certificate validation

main/ZmqttDiscovery.ino

@@ -1300,4 +1300,6 @@ void pubMqttDiscovery() {
 #    endif
 #  endif
 }
+#else
+void pubMqttDiscovery() {}
 #endif