Add notification popups (#540)

* Add notifications prototype

* Add timeout

* Improve function name

* Faster timeouts and fully clickable

* Update remove padding from old X button

* Only auto-dismiss when viewport is open

* Start auto dismiss once viewed

* Avoid redundantly displaying widget text as notifs

* Add sound effect

* Add setting for notifications

* Remove duplicate PluginSettings.StudioProvider

* Use short pop sound effect

* Fix broken audio, thanks Roblox

* Use e instead of createElement

plugin/src/playSound.lua

@@ -0,0 +1,22 @@
+-- Roblox decided that sounds only play in Edit mode when parented to a plugin widget, for some reason
+local plugin = plugin or script:FindFirstAncestorWhichIsA("Plugin")
+local widget = plugin:CreateDockWidgetPluginGui("Rojo_soundPlayer", DockWidgetPluginGuiInfo.new(
+	Enum.InitialDockState.Float,
+	false, true,
+	10, 10,
+	10, 10
+))
+widget.Name = "Rojo_soundPlayer"
+widget.Title = "Rojo Sound Player"
+
+return function(soundId)
+	local sound = Instance.new("Sound")
+	sound.SoundId = soundId
+	sound.Parent = widget
+
+	sound.Ended:Connect(function()
+		sound:Destroy()
+	end)
+
+	sound:Play()
+end