Add guide for changing Wi-Fi hotspot password via device-admin (#52)

This PR adds a how-to usage guide for the functionality added by
openUC2/machine-admin#41 .

This work is tracked on Notion at
https://www.notion.so/Support-changing-the-Wi-Fi-hotspot-password-from-the-Machine-Admin-app-3224e612c78a809cbebcdb052a8545de?source=copy_link

Author: ethanjli

docs/usage/components/os/guides/day-1/security.md

@@ -14,11 +14,19 @@ Because openUC2 OS comes with some default settings which make it less secure an
 
 ### How to change the Wi-Fi hotspot's password
 
+#### via Machine Administration
+
+1. [Open the browser app](./access.md#browser-apps) for Machine Administration.
+2. Open the Internet Access page.
+3. In the "Wi-Fi hotspot" section, enter a new password (at least 8 characters long, and up to 63 characters long) and press the "Update and restart" button.
+
+#### via the terminal
+
 By default, the password used for [connecting to the machine's Wi-Fi hotspot](./connectivity.md#via-the-machines-wi-fi-hotspot) is `youseetoo`.
 You should change this password to something more secure:
 
 1. [Enter the machine's terminal](./access.md#the-machines-terminal).
-2. Run the following command and follow the displayed instructions:
+2. Run the following command and follow the displayed instructions in order to enter a new password (at least 8 characters long, and up to 63 characters long):
    ```bash
    read -sp "Enter a new password: " password && echo "psk=$password" | sudo tee >/dev/null \
       /etc/NetworkManager/system-connections.d/wlan0-hotspot/51-wifi-security-password.nmconnection