How can we set an attribute on the web.config related with application version or espace version? 

The goal is having something like this in the web.config

 <configuration>
   <appSettings>
     <add key="AppName" value="Oustsystems Application" />
     <add key="AppVersion" value="1.2.3" />
   </appSettings>
   <system.web>

where the AppName and AppVersion are filled dynamically by the espace or application variables