Support double wildcards in actor deployment config

[stijnherreman]

Akka supports double wildcards in the actor deployment configuration. This is documented here (it's missing in the current docs):

you can use double-wildcards in the last position to match all child actors and their children recursively: /someParent/**

The relevant PR for this feature is akka/akka#20525. See https://github.com/akka/akka/blob/6278968af56f36b8ff3fd4a0a443e5218bceb838/akka-actor/src/main/scala/akka/util/WildcardIndex.scala for current version of this file.

It would be great to have this available in Akka.NET too. This will allow simplifying configuration from

"/foo/*" {
	dispatcher = bar
}
"/foo/*/*" {
	dispatcher = bar
}
"/foo/*/*/*" {
	dispatcher = bar
}

to

"/foo/**" {
	dispatcher = bar
}

[Aaronontheweb]

This will be released as part of Akka.NET v1.4.11