Add shortcut to install an app to Private space

Introduce long-press shortcut to install a copy
of the main user app to private space.

Test: manual, installed apps in different stores
and tried shortcut
https://screenshot.googleplex.com/6oAVamTytiYmvPC.png
Bug: 316118005
Flag: ACONFIG com.android.launcher3.Flags.enable_private_space_install_shortcut DEVELOPMENT

Change-Id: I702cd2a27388e3cc6e9e126308d5479836ba6655
diff --git a/aconfig/launcher.aconfig b/aconfig/launcher.aconfig
index 22ed567..0e11f4b 100644
--- a/aconfig/launcher.aconfig
+++ b/aconfig/launcher.aconfig
@@ -104,3 +104,10 @@
     description: "Enables support for archived apps in Launcher3, such as empty progress bar etc."
     bug: "210590852"
 }
+
+flag {
+    name: "enable_private_space_install_shortcut"
+    namespace: "launcher"
+    description: "Enables long-press shortcut to install a copy of an app to Private space"
+    bug: "316118005"
+}