Add a health check for umbraco application url

[elit0451]

Details

• Adding a new health check which checks if the value of umbracoApplicationUrl is set in the umbracoSettings.config file;
• There is also the option to set it according to the site URL that you are currently using.

Test

• Navigate to the Settings section > Health Check > Security
• Use the Check group button
• Verify that the information displayed in Application URL Configuration part is correct
  • Ex: If umbracoApplicationUrl="" in your umbracoSettings.config file, you will see a warning (⚠️) and you will be able to set its value through the newly added button (Set Umbraco application URL in Config)
• After clicking the button it should result in success (✔️) and the value in the config should be updated with the application's URL

[Zeegaan]

Tested this and it works great 👍

Code LGTM! 👓