Add mirror command

[p-x9]

struct Item {
    var title: String = "hello"
    var color = Color.red
    var id = UUID()
}

(lldb) mirror item
title: Swift.String = hello
color: SwiftUI.Color = red
id: Foundation.UUID = F0C09CD1-09B7-4D7D-9EF3-24C908442E89