Add Hibiscus server homebanking plugins

1. Last account update age in hours
2. Account balances

The plugins have been in use for several months now and warn
when the balance of accounts drop below a configurable value,
and when Hibiscus stopped updating data because a TAN needs to
be entered manually after 90 days.

The plugins directly query the MySQL database of a Hibiscus server
instance.
See https://www.willuhn.de/products/hibiscus-server/ for more information.

plugins/hibiscus/hibiscus_last_account_update

@@ -0,0 +1,99 @@
+#!/bin/bash
+# -*- sh -*-
+set -e
+set -o pipefail
+
+: << =cut
+
+=head1 NAME
+
+hibiscus_last_account_update - Age of the last bank account update
+
+Connects to the database of a "Hibiscus Server" homebanking instance.
+Checks bank accounts and returns the balance ("Saldo") update date of
+the account that was updated least recently.
+
+This script helps to get notified when the automatic updates stopped
+because a TAN needs to be entered manually after 90 days.
+
+=head1 CONFIGURATION
+
+=head2 ENVIRONMENT VARIABLES
+
+ host      - Hostname of MySQL/MariaDB server
+ user      - Database user
+ password  - Database password
+ database  - Database name
+ mysql     - MySQL/MariaDB binary
+ host_name - To put the graph onto a different host
+
+=head2 CONFIGURATION EXAMPLE
+
+  [hibiscus_*]
+  env.user hibiscususer
+  env.password thisismypassword
+  env.mysql /usr/bin/mariadb
+
+=head1 REQUIREMENTS
+
+"bash" and "mysql"/"mariadb" are required.
+
+"bash" instead of "sh" needed because of "set -o pipefail", which is not
+supported in Debian 12 yet.
+
+=head1 SEE ALSO
+
+https://www.willuhn.de/products/hibiscus-server/
+
+=head1 AUTHOR
+Christian Weiske <cweiske@cweiske.de>
+
+=head1 LICENSE
+
+AGPL-3.0-only https://spdx.org/licenses/AGPL-3.0-only.html
+
+=head1 MAGIC MARKERS
+
+#%# family=manual
+
+=cut
+
+# variables
+database=${database:-hibiscus}
+host=${host:-localhost}
+user=${user:-}
+pass=${password:-}
+mysql=${mysql:-/usr/bin/mysql}
+host_name=${host_name:-}
+
+
+case $1 in
+   config)
+       echo "graph_title Hibiscus last account update"
+       echo "graph_vlabel Age in hours"
+       echo "graph_args --base 1000 -l 0"
+       echo "graph_category banking"
+       echo "graph_order age"
+       echo "age.label Oldest account update age"
+       echo "age.draw AREA"
+       echo "age.warning 72"
+       if [ -n "$host_name" ]; then
+           echo "host_name $host_name"
+       fi
+       exit 0;;
+esac
+
+age_hours=$(
+    echo "\
+        SELECT HOUR(TIMEDIFF(NOW(), saldo_datum)) AS age\
+        FROM konto\
+        WHERE flags IS NULL\
+        ORDER BY age DESC\
+        LIMIT 1"\
+        | $mysql\
+              --skip-ssl\
+              --skip-column-names\
+              -h"$host" -u"$user" -p"$password"\
+              "$database"
+)
+echo "age.value $age_hours"