[DAEMON-274] appcd-config: Added support for config layers to be used by plugins
|Appc Daemon 2.2.0
|Appc Daemon 2.3.0
|appcd-config, appcd-config-service, appcd-plugin
Plugin configs are loaded and mixed with the global config, but it's merged at a global level and once merged, remains merged until the daemon is stopped. It also doesn't namespace the plugin configs. To solve this,
appcd-config needs the ability to define config layers. There is a default root layer, but then each registered config file from plugin is a new layer. These plugin config layers are namespaced so that they don't conflict.
Note that this does not affect the user-defined config which overlays everything.
- Chris Barber 2019-04-06