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/init.server.lua

@@ -18,7 +18,7 @@ local App = require(script.App)
 local app = Roact.createElement(App, {
 	plugin = plugin
 })
-local tree = Roact.mount(app, nil, "Rojo UI")
+local tree = Roact.mount(app, game:GetService("CoreGui"), "Rojo UI")
 
 plugin.Unloading:Connect(function()
 	Roact.unmount(tree)
@@ -28,4 +28,4 @@ if Config.isDevBuild then
 	local TestEZ = require(script.Parent.TestEZ)
 
 	require(script.runTests)(TestEZ)
-end
+end