Create separate CurrencyPickerView and tighten up ContentView

Sources/SatsPrice/SatsPriceApp.swift

@@ -19,7 +19,7 @@ public struct RootView : View {
     }
 
     public var body: some View {
-        ContentView(.coinbase)
+        ContentView()
             .task {
                 logger.log("Welcome to Skip on \(androidSDK != nil ? "Android" : "Darwin")!")
                 logger.warning("Skip app logs are viewable in the Xcode console for iOS; Android logs can be viewed in Studio or using adb logcat")