feat(networks): the network pages on Bootstrap's cards, tables and dialogs

As the storage pages; reviewed with Codex.

- The list is a card per network: its name with Active or Stopped and
  Autostart badges, its type (network_mode: Isolated, NAT, Routed,
  Open, Bridge, Macvtap, SR-IOV), its device, and each address with
  its DHCP range; a bridge or macvtap network's addresses come from
  the outside network.
- A network's page: its heading starts or stops it, the menu sets
  autostart and deletes a stopped one. A Network card tells its state,
  type, bridge or interface, MAC and what the type does; a card per
  address (every <ip>, each with its DHCP range dialog, which libvirt
  takes on a stopped network); its fixed addresses of every subnet in
  one table, searched, each with Edit and Delete, one dialog adding
  and editing them; the VMs whose definition names it, connected or
  configured, linked (wvmNetwork.get_vms, one domain listing, a VM
  undefined meanwhile left out); its
  bandwidth limits where libvirt sets them (not on macvtap or SR-IOV
  networks), in KiB/s, from the saved definition with a note that a
  running network takes them when restarted; its XML in an accordion.
  The page reads the running and the saved definition once each, and
  only to render itself: its actions, which all redirect, read nothing
  of it first.
- The New network dialog is one form, as the New pool one: the type
  as radio cards (the radio_card.html include, now shared by both),
  the chosen type's fields only, IPv6 with its box, a bridge or
  interface suggested from the host's (get_host_interfaces, not the
  bridges libvirt made for its own networks); a refused network or
  one libvirt refuses opens the dialog again with what was entered,
  the reasons beside the fields and focus on the first.
- What the New pool and New network dialogs share is one script,
  static/js/choice_dialog.js: the radio cards show their fieldsets
  (data-kinds) and a refused form opens again focused on its first
  refused field; each dialog keeps only its own changes.
- The fixed-address dialogs per family go to the page's own dialog.

networks/tests/test_network_changes.py

@@ -1,10 +1,10 @@
-"""A network's addresses are read from its XML however libvirt writes it,
-each <ip> by its own index; a change starts from the saved definition, so
-two in a row keep each other; a fixed address is found by the address it
-had and checked against its subnet; the XML editor defines only this
-network; a network that does not start is not left defined. Runs on a
-private libvirt test driver: "test:///default" is shared by the whole
-process."""
+"""A network's addresses are read from its XML however libvirt writes it, each
+<ip> by its own index; a page reads each definition once; a change starts
+from the saved definition, so two in a row keep each other; a fixed address
+is found by the address it had and checked against its subnet; the XML
+editor defines only this network; a network that does not start is not left
+defined. Runs on a private libvirt test driver: "test:///default" is shared
+by the whole process."""
 
 import tempfile
 from unittest.mock import MagicMock, patch
@@ -61,12 +61,13 @@ class NetworkChangeTests(SimpleTestCase):
     def saved(self):
         return etree.fromstring(self.conn.networkLookupByName("lab").XMLDesc(libvirt.VIR_NETWORK_XML_INACTIVE))
 
-    def test_the_page_reads_the_xml_once(self):
+    def test_the_page_reads_each_definition_once(self):
+        # the running one for its addresses, the saved one for its limits and the XML editor
         net = self.network()
         with patch.object(net.net, "XMLDesc", wraps=net.net.XMLDesc) as xml:
             net.get_ip_networks(), net.get_network_forward(), net.get_network_mac(), net.get_qos()
-            net.get_bridge_device()
-        self.assertEqual(xml.call_count, 1)
+            net.get_bridge_device(), net.get_mode(), net.saved_xml
+        self.assertEqual(xml.call_count, 2)
 
     def test_the_ipv4_address_after_an_ipv6_one_keeps_its_index(self):
         ipv6, ipv4 = self.network().get_ip_networks()
@@ -151,7 +152,7 @@ class NetworkChangeTests(SimpleTestCase):
     def test_the_xml_editor_takes_an_encoding_declaration(self):
         self.conn.networkLookupByName("lab").destroy()
         net = self.network()
-        net.edit_network('<?xml version="1.0" encoding="UTF-8"?>\n' + net.config_xml().replace("virbr9", "virbr6"))
+        net.edit_network('<?xml version="1.0" encoding="UTF-8"?>\n' + net.saved_xml.replace("virbr9", "virbr6"))
         self.assertEqual(self.saved().xpath("bridge/@name"), ["virbr6"])
 
     def test_a_fixed_address_is_of_the_subnet_and_its_own(self):
@@ -165,7 +166,7 @@ class NetworkChangeTests(SimpleTestCase):
     def test_the_xml_editor_defines_this_network_only(self):
         self.conn.networkLookupByName("lab").destroy()  # its definition read back at once
         net = self.network()
-        xml = net.config_xml()
+        xml = net.saved_xml
         for other, why in ((xml.replace("<name>lab</name>", "<name>other</name>"), "must define network lab"),
                            (xml.replace(net.net.UUIDString(), "11111111-2222-3333-4444-555555555555"), "keep the network's UUID"),
                            ("<network>", "not valid")):