Update Nextcloud to 26 and instructions (#955)

* Fix DAV Nextcloud warning

https://www.reddit.com/r/NextCloud/comments/sd7anx/your_web_server_is_not_properly_set_up_to_resolve/

* Add new version 26

* Add random password

* Improve instructions

* Tweak instructions

public/v4/apps/nextcloud.yml

@@ -56,7 +56,7 @@ caproverOneClickApp:
     variables:
         - id: $$cap_nextcloud_version
           label: NextCloud Version
-          defaultValue: 25.0.6
+          defaultValue: 26.0.3
           description: >-
               Check out their Docker page for the valid tags https://hub.docker.com/_/nextcloud?tab=tags
 
@@ -70,7 +70,7 @@ caproverOneClickApp:
           validRegex: /^([^\s^\/])+$/
         - id: $$cap_mariadb_version
           label: MariaDB (database) version
-          defaultValue: 10.6.12
+          defaultValue: 10.6.14
           description: Check out their Docker page for the valid tags https://hub.docker.com/_/mariadb?tab=tags
           validRegex: /^([^\s^\/])+$/
         - id: $$cap_db_user
@@ -90,6 +90,7 @@ caproverOneClickApp:
           validRegex: /^([a-zA-Z0-9\@\.])+$/
         - id: $$cap_admin_pass
           label: admin password
+          defaultValue: $$cap_gen_random_hex(10)
           description: Password for the Nextcloud admin user.
           validRegex: /.{8,}/
         - id: $$cap_http_https_cors
@@ -109,14 +110,20 @@ caproverOneClickApp:
 
 
             For better performances and compliance, click on "edit default nginx configuration" button then
-            below "proxy_set_header X-Forwarded-Proto $scheme;"
-            add "add_header Strict-Transport-Security "max-age=15552000; includeSubDomains" always;"  into the nginx configuration.
+            below `proxy_set_header X-Forwarded-Proto $scheme;`
+            add `add_header Strict-Transport-Security "max-age=15552000; includeSubDomains" always;`  into the nginx configuration.
 
-            You can see HSTS parts of the nextcloud security documentation https://docs.nextcloud.com/server/21/admin_manual/installation/harden_server.html for further informations
+            For DAV add after `/.well-known/captain-identifier` section 
+
+            `location /.well-known/carddav {return 301 $scheme://$host/remote.php/dav;}`
+
+            `location /.well-known/caldav {return 301 $scheme://$host/remote.php/dav;}`
+
+            You can see HSTS parts of the nextcloud security documentation [https://docs.nextcloud.com/server/21/admin_manual/installation/harden_server.html](https://docs.nextcloud.com/server/21/admin_manual/installation/harden_server.html) for further informations
 
 
-            You can also scan your nextcloud instance on https://scan.nextcloud.com/
-    displayName: nextcloud
+            You can also scan your nextcloud instance on [https://scan.nextcloud.com/](https://scan.nextcloud.com/)
+    displayName: Nextcloud
     isOfficial: true
     description: Nextcloud is a suite of client-server software for creating and using file hosting services
     documentation: Taken from https://hub.docker.com/_/nextcloud