Configuration reload

[thangchung]

Check if we can make the configuration re-load in the run-time. That's mean that we need to detect and reload when the environment variables changes (not sure it can work).

References:

• https://andrewlock.net/reloading-strongly-typed-options-in-asp-net-core-1-1-0/
• https://rimdev.io/strongly-typed-configuration-settings-in-asp-net-core-part-ii/
• https://weblog.west-wind.com/posts/2016/may/23/strongly-typed-configuration-settings-in-aspnet-core