conf_d:conf_d_configuration/3

Arguments:

`Available`	- is a directory or alias providing the available configurations (e.g., `config_available(.)`)
`Enabled`	- is a directory or alias providing the installed configuration (e.g., 'config-enabled')
`Configs`	- is a list if Key-[Example,Installed], where either is (-) or a config data item as required by conf_d_member_data/3. The list is sorted on Key.