In editor tutorials: Welcome dialog and table of contents [MTT-8698], [MTT-8694]

[RikuTheFuffs]

Description

• Added a welcome dialog to guide users on their first time experience
• Added a Table of Contents with helpful resources, that can be accessed from the Tutorials > Show Tutorials menu

Issue Number(s)

• https://jira.unity3d.com/browse/MTT-8694
• https://jira.unity3d.com/browse/MTT-8698

How to test/validate

1. Clone this branch
2. Open it with Unity
3. The welcome dialog will show up
4. Go to Tutorials > Show Tutorials to open the Table of Contents
5. Click all the links to ensure they work

Contribution checklist

• Release notes have been added to the project changelog file and/or package changelog file
• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• JIRA ticket ID is in the PR title or at least one commit message
• Include the ticket ID number within the body message of the PR to create a hyperlink

[unity-cla-assistant]

All committers have signed the CLA.

[gopher-atz]

small FTUE feedback:

• i would make the the welcome dialog just 2 lines bigger in y, so you can get rid of the scrollbar completely
• the tutorial window is (in my case) docked at the very right side of the editor and squashed
  , i would consider to have it floating as well initially (people can still doch later)

[gopher-atz]

when the tutorial window gets smaller in y, there's some layout issues with the menu bar on top.
it gets overlayed by the content section and you cannot click the buttons in tghe overlap zone.

[RikuTheFuffs]

1. i would make the the welcome dialog just 2 lines bigger in y, so you can get rid of the scrollbar completely
2. the tutorial window is (in my case) docked at the very right side of the editor and squashed
3. when the tutorial window gets smaller in y, there's some layout issues with the menu bar on top.

@gopher-atz I agree with you but we do not control the size or position of those elements. They're managed by the tutorial framework and tutorial authoring tools packages, internally.

On 1: What we can do is removing 2 lines from the welcome dialog. Here's the updated copy.

On 2: the docking to the right of the inspector is the default In-Editor Tutorials behaviour. To solve the squashing I can try setting a project layout that is loaded automatically at startup, and give more space to the tutorial window there.

This is how it should show up now, can you have another look? (Tutorials > Authoring > Debug > Run startup code)

On 3: it's an IET bug that should be addressed cc @guillaumed-unity

[RikuTheFuffs]

The failing tests were already failing on develop, they won't be fixed in this PR. (see #889 )