[feat] Support path expression for Key annotation

[syhily]

Support the path expression for @Key annotation like the picture above.

[keykey7]

it has some drawbacks as it could conflict with another (nested) key. Otherwise it's definitely possible.
Depending on the usecase, this could also be an alternative (even though quite verbose):

interface B {
	@Default("${settings.dimension.filter-null-value}")
	boolean filterNullGrouping();
	S settings();
}
interface S {
	D dimension();
}
interface D {
	@Key("filter-null-value")
	boolean filterNullValue();
}

[syhily]

How about introducing a new annotation called @Path. It wouldn't inherit the parent's definition, but just query the value from the given path.

interface A {
	B some();
	interface B {
		@Path("settings.dimension.filter-null-value")
		boolean filterNullGrouping();
	}
}