add NUT Server to the catalog

- NUT Server (instantlinux/nut-upsd) runs the Network UPS Tools server for a UPS connected to the host by USB: the installation proposes the UPS the host detects, passes it to the container, generates the password of the upsmon user and starts with the host; clients such as PeaNUT connect on port 3493.
- A recipe can ask for the UPS of the host: without one, the installation stops and says so, and the advanced installation lets the node be typed by hand.
- The catalog lists 335 applications.
- Tests for the proposed UPS, a host without one and the recipe.

.github/scripts/tests/test_command_descriptions.py

@@ -213,6 +213,8 @@ class CommandDescriptionsTests(unittest.TestCase):
                     # Model the bot's future output in temporary catalogs, just
                     # like the other pending keys above; never rewrite locales.
                     messages["scriptTerminal"].setdefault("endOfInput", english["scriptTerminal"]["endOfInput"])
+                    for key in ("noShell", "enterFailed"):
+                        messages["lxcTerminal"]["errors"].setdefault(key, english["lxcTerminal"]["errors"][key])
                     # The notification history panel texts await the bot as well.
                     for key, value in english["settings"]["notifications"]["history"].items():
                         messages["settings"]["notifications"].setdefault("history", {}).setdefault(key, value)