Moved per user post install actions to first-login script.

* The same mechanism (and the same PostInstallScript) is used for this.
* If a file first_login exists in ~/config/settings/boot, the first-login
  scripts are launched, and the file removed.
* This fixes adding the deskbar tray icons even when there is no Deskbar
  running yet (for example on first boot when the FirstBootPrompt
  starts), or, IOW bug #12275.

data/launch/system

@@ -80,7 +80,7 @@ job x-vnd.Haiku-cddb_lookup {
 }
 
 job post-install {
-	launch /bin/sh /system/boot/PostInstallScript
+	launch /bin/sh /system/boot/PostInstallScript "post install" /boot/system/settings/fresh_install /boot/system/boot/post-install
 	if file_exists /boot/system/settings/fresh_install
 }
 

data/launch/user

@@ -20,6 +20,11 @@ target desktop {
 		launch /bin/sh ~/config/settings/boot/UserBootscript
 	}
 
+	job first-login {
+		launch /bin/sh /system/boot/PostInstallScript "first login" ~/config/settings/first_login /boot/system/boot/first-login
+		if file_exists ~/config/settings/first_login
+	}
+
 	job create-installer-link {
 		# When run from a read-only medium a.k.a. live desktop
 		if {