Set App.base location

Jobs running as shells might need to send notifications which could include urls back to the framework. Shells live outside the main application and do not have access to the request, thus they do not know what the webroot is.

In order to address this problem we will introduce a new CMP confiuration, App.base ( database field app_base ), which will store COmanage webroot. Then the jobshell will write the value into the configuration key App.base at runtime. We will not use the core.php file because we want to avoid having the CMP admins editing configuration files.

The CMP app_base setting will be initialized or updated each time the CMP administrator logs in.

Not sure if we actually need to make the field editable