Add documentation for password recovery using email (#432)

Author: vishesh92

source/_static/images/default-login.png

@@ -807,4 +807,80 @@ The admin can also disable 2FA for a User using the action button as shown below
           If the admin themself loses the authenticator application or forgets the static PIN, then the admin
           will have to either use apikey to disable 2FA using the API setupUserTwoFactorAuthentication with
           enable flag to false or to do the database changes in 'user' table by clearing the columns
-          'is_user_2fa_enabled', 'key_for_2fa', 'user_2fa_provider' for the specific entry.
+          'is_user_2fa_enabled', 'key_for_2fa', 'user_2fa_provider' for the specific entry.
+
+Password Recovery for Users (Forgot Password)
+---------------------------------------------
+
+CloudStack supports password recovery using email. To enable this feature,
+set global setting `user.password.reset.enabled` to `true`. The following
+global settings are available to configure SMTP for password recovery.
+
+
+.. list-table:: Password Recovery Global Settings
+   :header-rows: 1
+
+   * - Global setting
+     - Default
+     - Description
+   * - ``user.password.reset.enabled``
+     - `false`
+     - Determines whether password recovery via email is enabled or not.
+   * - ``user.password.reset.ttl``
+     - `30`
+     - TTL in minutes for the token generated to reset the ACS user's password.
+   * - ``user.password.reset.email.sender``
+     - `null`
+     - Sender for emails sent to the user to reset ACS user's password
+   * - ``user.password.reset.smtp.host``
+     - `null`
+     - Host for SMTP server
+   * - ``user.password.reset.smtp.port``
+     - `25`
+     - Port for SMTP server
+   * - ``user.password.reset.smtp.useAuth``
+     - `false`
+     - Use auth in the SMTP server
+   * - ``user.password.reset.smtp.username``
+     - `null`
+     - Username for SMTP server
+   * - ``user.password.reset.smtp.password``
+     - `null`
+     - Password for SMTP Server
+   * - ``user.password.reset.mail.template``
+     - `Hello {{username}}!`
+       
+       `You have requested to reset your password. Please click the following link to reset your password:``
+       
+       `http://{{{resetLink}}}`
+       
+       `If you did not request a password reset, please ignore this email.`
+
+
+       `Regards,`
+
+       `The CloudStack Team`
+     - Template of mail sent to the user to reset ACS user's password. This uses
+       mustache template engine. Available variables are: `username`, 
+       `firstName`, `lastName`, `resetLink`, `token`.
+
+
+Once the global settings are configured, follow the below steps to reset the
+password for a user:
+
+#. Open the "Forgot Password" link on the login page.
+
+   .. figure:: /_static/images/default-login.png
+      :align:   center
+
+#. Enter your username and domain name and click on "Submit".
+
+   .. figure:: /_static/images/forgot-password.png
+      :align:   center
+
+#. An email will be sent to the User with a link to reset the password.
+
+#. Open the link in the email and set the new password.
+
+   .. figure:: /_static/images/reset-password.png
+      :align:   center