Make the unity plugin a package that can be imported by only putting the github link in the Unity Package Manager

[Morgan-6Freedom]

The plugin should follow thoses guidelines :
https://docs.unity3d.com/Manual/CustomPackages.html

and this layout :
https://docs.unity3d.com/Manual/cus-layout.html

[Morgan-6Freedom]

This will be the new way to install :

To import the package in Unity:

1. Open the package manager
2. Click [+]
3. Click "Add package from Git URL"
4. Copy past this link https://github.com/scenario-labs/Scenario-Unity.git?path=/package
5. Click "Add"

[Morgan-6Freedom]

1. Merge into dev
2. Quentin check it
3. Merge into main
4. Check if the changelog update it itself

[Morgan-6Freedom]

@qvaleroo : Put the security on /main/ and let only you + hervé the ability to merge dev into main.
Then merge dev => main

[Morgan-6Freedom]

When merge is done Need to notify Thimothy to change the documentation "how to install unity"