Qualify the Docker Hub image names, drop the gluetun branding

main qualified five charts' image references in 6c73ef8 on the same day this
chart would otherwise arrive carrying the pattern that was just cleared out.
The seven Docker Hub names now say where they come from: qmcgaw/gluetun, the
five linuxserver.io images and the busybox init image, the last as
docker.io/library/busybox since it is an official image. The three ghcr.io
names were already qualified - checked rather than assumed.

Verified with Renovate 44.41.0 in the official container (RENOVATE_PLATFORM=
local, RENOVATE_DRY_RUN=lookup) that the prefixed form still resolves under the
built-in helm-values manager, since that manager is the only thing keeping
these images updated: it extracts all ten, datasource docker, no skipReason and
no warnings, and returns concrete candidates for eight of them. A control run
against the unqualified form produced byte-identical results, so the prefix
changes nothing about what Renovate offers.

Trivy's trusted-registry check (KSV-0125) drops from ten findings to none, which
is what the registry list in ci/trivy/data/ksv0125.yaml documents as the point
of writing images this way.

Chart metadata: the icon was gluetun's logo and the description opened with a
list of four of the nine projects, both suggesting a "main app" the stack does
not have. The description now names none of them, and the icon field is omitted
rather than filled with another project's logo - every other chart's icon is its
one upstream's, and this chart has no such upstream. helm lint --strict notes
"icon is recommended" as INFO and still exits 0.

Rendered output differs in exactly the seven image prefixes and nothing else.

freesailarr/Chart.yaml

@@ -1,7 +1,10 @@
 apiVersion: v2
 name: freesailarr
-description: A Helm chart to deploy a Wireguard-tunneled media automation stack (gluetun, qbittorrent, the *arrs, seerr) on Kubernetes
-icon: https://raw.githubusercontent.com/qdm12/gluetun/master/doc/logo_256.png
+description: A Helm chart to deploy a Wireguard-tunneled media automation stack on Kubernetes - a VPN gateway with indexer, downloader, library managers, subtitle fetcher and request front end in one pod, all reaching the internet only through the tunnel
+# No icon on purpose: the stack has no single upstream, and every other chart's
+# icon is its one project's logo. Picking any of the nine here would suggest
+# the same false "main app" the versioning deliberately avoids. The field is
+# optional, so it is omitted rather than filled with an arbitrary choice.
 
 type: application