[MTT-8696][MTT-8692] Feat: 2D Space Shooter IET Welcome Dialog and Table of Contents (#264)

* fix: update CI editor version

* feat: add welcome dialogue

* fix: add description and title to welcome dialogue

* Feat: add Table of Contents to IET

fix: remove vscode again

* chore: remove in-project readme

* feat: show welcome dialog at startup and mention IET in changelog, fix: change forum link to discussions

* fix: remove typos and empty spaces from Table of Contents

* Fix: remove Update Panel Settings.asset change

* Update Settings.json to true

* Fix: Renamed banner and removed redundant code in TutorialCallbacks

* feat: add button to welcome page which leads to network scene

* Fix: remove second welcome dialogue button, first button closes window as well now

Title text adjusted to keep it coherent with other samples

Author: Elfi0Kuhndorf