api,manager: new InhibitDevice() method

This new method allows users of the ModemManager API to take full
control of a given device.

Unlike other operations in the API, the inhibition is maintained as
long as the caller exists in the bus, or until the same caller
uninhibits the device.

https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/98

introspection/org.freedesktop.ModemManager1.xml

@@ -106,6 +106,27 @@
       <arg name="properties" type="a{sv}" direction="in" />
     </method>
 
+    <!--
+        InhibitDevice:
+        @uid: the unique ID of the physical device, given in the
+              #org.freedesktop.ModemManager1.Modem:Device property.
+        @inhibit: %TRUE to inhibit the modem and %FALSE to uninhibit it.
+
+        Inhibit or uninhibit the device.
+
+        When the modem is inhibited ModemManager will close all its ports and
+        unexport it from the bus, so that users of the interface are no longer
+        able to operate with it.
+
+        This operation binds the inhibition request to the existence of the
+        caller in the DBus bus. If the caller disappears from the bus, the
+        inhibition will automatically removed.
+    -->
+    <method name="InhibitDevice">
+      <arg name="uid"     type="s" direction="in" />
+      <arg name="inhibit" type="b" direction="in" />
+    </method>
+
     <!--
         Version: