Decouple appVersion from gluetun in wording and value

The previous commit moved every image tag into values.yaml but left appVersion
described as a marker "for the gluetun line", to be updated together with
gluetun.image.tag. That still asserts a coupling the chart does not have, and
the value v3.41.1 confirmed it at a glance.

appVersion is now 1.0.0 (version 1.0.0+up1.0.0): the chart's own version
marker, freely chosen and tied to no upstream. The texts say that instead of
the old coupling in Chart.yaml, values.yaml and the two README passages. The
README's remaining true statement is kept but generalized - renovate-bump-chart
bumps the patch level on an unchanged appVersion for all nine images alike,
which is not a gluetun special case.

Also corrected on the way: the busybox init image comment claimed it was
"pinned independently of appVersion (which tracks gluetun)". Neither half holds
any more - appVersion tracks nothing, and every image in the chart is pinned
the same way.

No functional change: the rendered gluetun image is qmcgaw/gluetun:v3.41.1
before and after.

freesailarr/Chart.yaml

@@ -5,15 +5,17 @@ icon: https://raw.githubusercontent.com/qdm12/gluetun/master/doc/logo_256.png
 
 type: application
 
-version: 1.0.0+upv3.41.1
-# Hand-maintained marker for the gluetun line this chart is built around - it
-# is NOT the source of any image tag. All nine images, gluetun included, are
-# pinned in values.yaml so Renovate's helm-values manager can propose them
-# there; consequently this chart has no app-version block in renovate.json5 and
-# nothing rewrites this field automatically. Update it by hand together with
-# gluetun.image.tag, otherwise the +up suffix of version: stops describing what
-# the chart deploys.
-appVersion: "v3.41.1"
+version: 1.0.0+up1.0.0
+# The chart's own version marker, freely chosen and tied to no upstream. The
+# stack bundles nine independently versioned projects, so there is no single
+# "app version" to track here.
+#
+# It is NOT the source of any image tag: all nine images are pinned in
+# values.yaml, where Renovate's helm-values manager proposes them. Nothing
+# rewrites this field automatically - the chart has no app-version block in
+# renovate.json5 and is not in the change-app-version.yml choice list. Raise it
+# by hand when you want to mark a new edition of the chart as a whole.
+appVersion: "1.0.0"
 
 maintainers:
   - name: jklein