feat(interfaces): the interface pages on Bootstrap's cards, tables and dialogs

As the storage and network pages; plan reviewed with Codex.

- The list is grouped by type (bridges, bonds, VLANs, ethernet; a type
  the host has none of is left out), three cards a row, with a search
  of their names, MACs and networks (table_filter.js, which now takes
  any element with data-search as a row); a card per interface: its link
  as the kernel reports it (up green, down grey, another state or
  unknown told as such, no red card for a link that is merely down),
  MAC, MTU, speed when known, the members it reports and the libvirt
  networks that use it, linked.
- An interface's page: an Interface card (type, libvirt's own state
  where it manages interfaces, link, start mode, MAC, MTU, speed, STP,
  networks using it); on a host whose libvirt changes interfaces, a
  card per family with how it is addressed and its addresses; the
  members of a bridge, bond or VLAN with their link and speed, or that
  none is reported; for a bridge, the running VMs' cards on it,
  directly or through a network using it, with their tap and MAC,
  linked (wvmInterface.get_vms: one domain listing). Not the bridge's
  delay: netcf tells it in seconds, the udev backend in hundredths.
  Start or Stop in its heading, Delete in its menu, disabled while it
  runs, on hosts that can change interfaces only.
- A host whose libvirt only reads interfaces says so once, with that
  it does not tell their addresses, instead of "None" on every page.
- The New interface dialog is one form, as the New pool and New
  network ones (choice_dialog.js, radio_card.html): Bridge or
  Ethernet, a bridge's member from the devices it can take, an
  ethernet interface's device from the ones the host does not define
  yet, a static address's fields with its choice; a refused interface,
  or one libvirt refuses, opens it again with what was entered; a made
  one opens its page.
- networks_by_device maps the libvirt networks to their bridges or
  interfaces on the page's own connection.

webvirtcloud/tests/test_status_contrast.py

@@ -1,7 +1,7 @@
-"""Status colours keep their contrast on every theme: an interface card's
-header, and a status word, is the theme's pale status background with its
-dark status text, a pair that does not depend on the page's background
-(dark themes keep light-mode emphasis colours)."""
+"""Status colours keep their contrast on every theme: a status word is the
+theme's pale status background with its dark status text, a pair that does
+not depend on the page's background (dark themes keep light-mode emphasis
+colours)."""
 
 from unittest.mock import PropertyMock, patch
 
@@ -26,17 +26,6 @@ class StatusContrastTests(TestCase):
         self.assertEqual(response.status_code, 200)
         return html.fromstring(response.content)
 
-    def test_card_headers_are_pale_with_dark_text(self):
-        for name in ("interfaces",):
-            with self.subTest(page=name):
-                headers = self.page(name).xpath("//div[contains(@class, 'card-header')]")
-                self.assertTrue(headers)
-                for header in headers:
-                    classes = header.get("class").split()
-                    self.assertTrue({"bg-success-subtle", "bg-danger-subtle"} & set(classes), classes)
-                    link = header.xpath(".//a")[0].get("class").split()
-                    self.assertTrue({"text-success-emphasis", "text-danger-emphasis"} & set(link), link)
-
     def test_status_words_are_pale_badges_with_dark_text(self):
         # the test driver has no node memory statistics for the host row
         with patch.object(Compute, "ram_usage", new_callable=PropertyMock, return_value=1):