Expose information regarding deprecated environment settings via API

[arnaudsjs]

The Inmanta server has a concept of deprecated environment settings. However, this information is not exposed via the API. That way it's not possible for the web-console to indicate which environment settings have been deprecated.

Information to expose:

• Which setting have been deprecated.
• When a setting was deprecated in favor of another setting, indicate whether the old or the new setting is currently being used.

When this ticket is implemented create a ticket on the web-console to highlight the deprecated settings

Question: Are we going to implement this given that all deprecated environment settings will be removed in the next major release (See: #6084)?