Update MineOS docs

We create again a dedicated login user, to work around the login issue, with MineOS not supporting the new default yescrypt password hashing algorithm. Add an info about how to change the password, since it is required to explicitly define SHA512 as hashing algorithm.

Author: MichaIng

docs/software/gaming.md

@@ -125,8 +125,14 @@ MineOS allows you to create multiple Minecraft servers with ease, using a simple
 
     - URL: `https://<your.IP>:8443`  
       You can safely ignore the certificate "warning" if one appears.
-    - Username: `root`
-    - Password: The same as your root login password. Default is `dietpi`
+    - Username: `mineos`
+    - Password = `<globalSoftwarePassword>` (default: `dietpi`)
+
+    To change the password to `myPassword`, run the following command:
+
+    ```sh
+    sudo chpasswd --crypt-method SHA512 <<< 'mineos:myPassword'
+    ```
 
 === "1st run setup"