Replace the obsolete no-dependencies rationale in every chart helper

The doc comments on the resources and defaultedDict helpers justified the
copy-per-chart with "charts in this repo deliberately have no dependencies".
That rule fell with #214: a dependency is admissible now, just expensive, and
it sits in the README as guideline 14, not 13. The justification still holds,
but its reason is a different one - sharing the helper would mean a library
chart, a second artefact to publish, version and pull for something that
changes about once a year. searxng got that wording in PR #38; this carries it
to the remaining 22 charts, 41 occurrences in all.

Comments only: every touched chart renders byte-identical against its
ci/<chart>/test-values.yaml. Each published chart takes a patch bump,
appVersion and +up suffix untouched; template-chart is never published and
takes none, but is corrected because every new chart inherits from it.

Two repo files carried the same claim at no version cost:
validate-charts.yml explained the all-charts quantity render test with it, and
change-app-version.yml still counted nine images for freesailarr - MediathekArr
made it ten.

.github/workflows/validate-charts.yml

@@ -157,8 +157,9 @@ jobs:
     # against - resource quantities formatted with printf "%v", where float64
     # flips to exponential notation above ~1e6 - lives in the resources helper,
     # and that helper is copied into every chart's templates/_helpers.tpl,
-    # because charts here have no dependencies. So it comes back by copy: a new
-    # chart started from an older one, or from template-chart before the fix.
+    # because sharing it would mean a library chart (README, guideline 14). So
+    # it comes back by copy: a new chart started from an older one, or from
+    # template-chart before the fix.
     # In that PR the chart is new and its copy of the bug is in no diff anyone
     # reads. Running over everything also means there is no list to maintain -
     # adding a chart enrolls it. Two renders per chart, no cluster, a few