Readme added

[CesiumBen]

Summary

Base Readme added in. Also included change to PR template since after adding in a new tutorial you would need to add in a new section.

Author checklist

• Tutorial for N/A
• Has the new tutorial been integrated into the main level? N/A
• Have you done a full self-review of the code and blueprints? N/A
• Have you tagged a primary reviewer? Yes
• Are there any remaining tasks to do or blocking questions to answer before we can merge this? No

Testing plan

Review text

Reminders for reviewers

Thank you for taking the time to review this PR. By approving a PR you are taking as much responsibility for these changes as the author. Please keep these points in mind throughout the review process:

• Review and run all parts of the test plan on this branch and verify it matches expectations.
• Review the code and make sure you do not have any remaining questions or concerns. You should understand why this code change fixes the issue and agree that it's the best approach to doing so.
• Review the automated tests and make sure there are no missing tests or edge cases.
• When you feel this is ready bump it to a second reviewer or merge.

[argallegos]

This looks good! Be sure to link to the tutorials when the tutorials go live.

[shehzan10]

@CesiumBen Apologies for the delayed feedback here. A few notes:

• The first paragraph should be a short, concise message about what the user can expect in this repo.
• Link to the VR Tutorials on our website right away
• The note about the input bindings can go lower in the Readme IMO
• In the Getting Started Section, also point the user to the Getting Started Tutorial on the website.
• Under Tutorial Descriptions but before Tutorial 1, give the user an overview of how the tutorials are structure - for example, the each tutorial is its individual level and builds on the previous level
• Invite feedback and what is the mechanism? Do you want contributors to open community forum posts or GitHub issues? How do you want to divide what goes where? (you may choose to follow default Cesium for Unreal strategy - bugs and features in GitHub, questions and feedback in community forum)