Discover subsystems. We need to distinguish two cases denoted by the path
plugin config:
- Path is a single 'word': here the value denotes a key in the resource path
of AS7, that identifies a child type see e.g. the Connectors below the JBossWeb
service in the plugin descriptor. There can be multiple resources of the given
type. In addition it is possible that a path entry in configuration shares multiple
types that are separated by the pipe symbol.
- Path is a key-value pair (e.g. subsystem=web ). This denotes a singleton
subsystem with a fixes path within AS7 (perhaps below another resource in the
tree.