nut: Encrypt upsd user passwords with age

Switching from Ansible Vault to age.

I've changed the `upsd.users` template somewhat in order to handle the
`password` property separately.  Now, items in the `nut_users` list
are objects with properties instead of lists of objects with properties.
The latter was done to support repeating options (`actions` and
`instcmds`), but that is more appropriately handled with lists of
values.

This value is encrypted with the following public key:

    age1c6swn9tm0502jd3e0yszfd4qd7lgx2nd9uk0hruuckhx7zpn3utqhau7mz

group_vars/nut/main.yml

@@ -1,6 +1,14 @@
 nut_users:
   homeassistant:
-  - password: '{{ vault_nut_user_passwords.homeassistant }}'
+    password: |
+      -----BEGIN AGE ENCRYPTED FILE-----
+      YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSAxZUZleGt3emxXdDFtcEtN
+      Wll3K0hrS2c2M1oyMWh2VlBnMER0bkZOb1VVCnU3aTI2eVJoV1dKNWxEd0VnbVNa
+      NlMxVWRuZWpNbTJRVUhWR2w3bUlwaEUKLS0tIGZLcGNQRy9LNUF1Y0JzZEZGdXBn
+      bUJjYlBSSEYwRUpwemlMZ0xCZnpTS2cKUFke27YDeTME9OBgEcQdbJ3jsDZS43km
+      tK61kLMcexq3lXQb30gx4fzMuYa0MXFygawscTnxTrOrXUd36Iga4A==
+      -----END AGE ENCRYPTED FILE-----
+
 nut_ups:
   apc1500:
   - driver: usbhid-ups
@@ -18,6 +26,7 @@ nut_ups:
   - product: .*1300G.*
   - pollonly: enabled
   - pollinterval: 1
+
 collectd_nut_ups: >-
   {{
     ["localhost"]