chore(apps): move icons into the apps folder (#3139)

* chore(apps): move icons into the apps folder

* rename to `icon.png`

* replace solr image

* remove `docs/` from gitignore

* move app specific docs into app folder [skip ci]

* fix some links

* chore(apps): update image links temporary

charts/stable/nextcloud/Chart.yaml

@@ -20,7 +20,7 @@ deprecated: false
 description: A private cloud server that puts the control and security of your own
   data back into your hands.
 home: https://github.com/truecharts/apps/tree/master/charts/stable/nextcloud
-icon: https://truecharts.org/_static/img/appicons/nextcloud.png
+icon: https://truecharts.org/img/appicons/nextcloud.png
 keywords:
 - nextcloud
 - storage

charts/stable/nextcloud/docs/installation_notes.md

@@ -0,0 +1,24 @@
+# Important Notes
+
+Nextcloud is a VERY picky Application and is VERY hard to support.
+For this reason we ask you not to file support requests on our Discord or Github, unless your issue is clearly caused by TrueCharts.
+
+While we consider the App layer "Stable", we simply cannot guarantee stability due to the nature of the Nextcloud Application inside the App.
+
+
+# Installation Notes
+
+Nextcloud generates it's `config.php` file on the first startup/installation. Therefore you have to set some values correctly on the first try.
+Otherwise you will have to either re-install the App or edit the `config.php` manually, with the latter being out of our support scope.
+The mentioned values are:
+  - TRUSTED_PROXIES
+  - NODE_IP
+  - Ingress, if you plan to use it.
+  - Data storage location, type (eg. PVC, hostPath).
+
+
+Also Nextcloud creates an Admin user on the first startup/installation, which you can only define it's username and password on the first install.
+Changing them later, will have no effect.
+The mentioned values are:
+  - NEXTCLOUD_ADMIN_USER
+  - NEXTCLOUD_ADMIN_PASSWORD