Rename every remaining voxip name to daynivo, with a one-time migration

Services (daynivo-kiosk-*, daynivo-network-guard, daynivo-boot-import),
programs in /usr/lib/daynivo-kiosk, folders /etc, /var/lib, /var/log and
/var/cache daynivo-kiosk*, the system user daynivo, DAYNIVO_* settings,
the plymouth theme, network profiles daynivo-eth0/wlan0, the image stage
and its first user daynivoadmin.

install.sh moves a kiosk installed up to 1.2.x over once: old services
stopped and removed, folders moved (configuration, password, browser
profile, logs) with symlinks under the old names, the voxip user renamed
with the same uid, network profiles renamed unless a change awaits
confirmation, and old leftovers removed. Tested by upgrading a configured
1.2.0 installation in a container, and running the install a second time.

Old names keep working where people type or place them: voxip-config.json,
voxip-authorized_keys, voxip-network-reset, voxip-kiosk-ctl, and
VOXIP_DEFAULT_URL / VOXIP_DEVICE_NAME for image builds.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

config/avahi-daynivo.service

@@ -0,0 +1,10 @@
+<?xml version="1.0" standalone='no'?>
+<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
+<service-group>
+  <name replace-wildcards="yes">Daynivo Kiosk Manager op %h</name>
+  <service>
+    <type>_http._tcp</type>
+    <port>8080</port>
+    <txt-record>path=/</txt-record>
+  </service>
+</service-group>