feat(Nextcloud): Improved installation_notes (#3315)

* Added more info to the install notes and added the guide from Discord to help with upgrades

* apply some changes

* Update charts/stable/nextcloud/docs/installation_notes.md

* Update charts/stable/nextcloud/docs/installation_notes.md

* Update charts/stable/nextcloud/docs/installation_notes.md

Co-authored-by: Stavros kois <s.kois@outlook.com>
Co-authored-by: Kjeld Schouten-Lebbing <kjeld@schouten-lebbing.nl>

charts/stable/nextcloud/docs/installation_notes.md

@@ -1,7 +1,14 @@
 # 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.
+The support staff on our Discord can help with the basic installation and
+getting Ingress to run with the chart, as that is that is the only recommended and supported installation method since 15.X.
+
+The support staff will not help with upgrades that fail from an earlier version than 15.X, we've included a
+[migration guide](migration_guide.md) to help with this upgrade.
+
+If you're having issues with the Nextcloud app/chart itself after basic installation we ask you not to file support
+requests on our Discord or Github, unless your issue is clearly caused by TrueCharts. It's, however, fine to ask in an, appropiate, other, non-support, channel!
 
 While we consider the App layer "Stable", we simply cannot guarantee stability due to the nature of the Nextcloud Application inside the App.
 
@@ -11,13 +18,9 @@ Nextcloud generates it's `config.php` file on the first startup/installation. Th
 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).
+- User 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.
+Also Nextcloud creates an Admin user on the first startup/installation. Changing them later, will have no effect.
 The mentioned values are:
 
 - NEXTCLOUD_ADMIN_USER

charts/stable/nextcloud/docs/migration_guide.md

@@ -0,0 +1,27 @@
+# Migration Notes
+
+This guide is provided as a resource to help taken from our Discord, but since 15.X is a breaking change
+there's no guarantees this will work, and you may have to install fresh
+
+We want to highlight that this is considered a completely new App, hence the "breaking change".
+For the best stability we would advice people to reinstall (with the option to save the users data).
+
+While we try to help people through migration and even have added some automated migration tooling,
+we cannot guarantee migration with breaking changes like these.
+
+The correct troubleshooting steps would be:
+
+- Remove any mention of "nextcloud_datadir" either in env-vars or config.php (if you manually added or altered it), we never supported this due to us expecting this change long beforehand
+- Remove any custom storage
+- Ensure config is set to "PVC"
+- Add `127.0.0.1` to the TRUSTED_PROXY setting like this: `172.16.0.0/16 127.0.0.1`
+- Stop and Start the old version to double-ensure the settings are applied
+- Apply the update
+- Wait for a good while (go grab lunch, eat it and drink a coffee afterwards)
+- Check if it worked out
+
+If not:
+
+- Manually ensure your nextcloud data structure is correct inside the App in both /var/www/html and /var/www/html/data
+- Double check if data directory is not set to anything other than /var/www/html/data (not set at-all is fine though)
+- Restart