fix(templates): the fields of the create modals are named by their labels

An accessibility scan with every modal opened found 49 fields without a
name: the labels of the instance create forms (custom, template and each
flavor's modal), the interface, network, secret and storage pool modals
did not point at their fields. Each label now has a for= and its field an
id, prefixed per form (and per flavor), so a click on the label focuses
the field too. The "Advanced" collapse buttons and the memory and
processing bars are named.

The VCPU config select had id="vcpu_mode" in each of these forms, nine
times on the create page; the unique-ID test did not see it as the test
driver reports no CPU modes. The id goes (nothing used it), and the test
now renders that branch.

webvirtcloud/tests/test_unique_ids.py

@@ -37,6 +37,7 @@ class UniqueIdTests(TestCase):
         with patch("vrtManager.connection.connection_manager.get_connection", return_value=conn), \
              patch("vrtManager.connection.wvmConnect.get_machine_types", return_value=["pc"]), \
              patch("vrtManager.connection.wvmConnect.get_nwfilters", return_value=[]), \
+             patch("vrtManager.connection.wvmConnect.get_cpu_modes", return_value=["host-model"]), \
              patch.object(libvirt.virConnect, "getMemoryStats", return_value={"total": 8 << 20, "free": 4 << 20, "buffers": 0, "cached": 0}), \
              patch.object(libvirt.virConnect, "getCPUStats", return_value={"kernel": 1, "idle": 1, "user": 1, "iowait": 0}):
             for name, keys in named_urls(get_resolver().url_patterns):