Make the XMPP server address configurable.

fix #3145

doc/biboumi.1.md

@@ -47,6 +47,12 @@ The configuration file uses a simple format of the form
   This password must be configured in the XMPP server, associated with the
   external component on *hostname*.
 
+`xmpp_server_ip`
+
+  The IP address to connect to the XMPP server on. The connection to the XMPP
+  server is unencrypted, so the biboumi instance and the server should normally
+  be on the same host. The default value is 127.0.0.1.
+
 `port`
 
   The TCP port to use to connect to the local XMPP component. The default

louloulibs/xmpp/xmpp_component.cpp

@@ -61,7 +61,7 @@ XmppComponent::XmppComponent(std::shared_ptr<Poller> poller, const std::string&
 
 void XmppComponent::start()
 {
-  this->connect("127.0.0.1", Config::get("port", "5347"), false);
+  this->connect(Config::get("xmpp_server_ip", "127.0.0.1"), Config::get("port", "5347"), false);
 }
 
 bool XmppComponent::is_document_open() const