[Cosmetic] New logo

[romainruaud]

The ElasticSuite logo will change with our new website and brand identity.

We should take care of changing it :

1. in the README file

2. in the Magento menu, it's done by using this font : https://github.com/Smile-SA/elasticsuite/tree/2.11.x/src/lib/web/fonts/elasticsuite

3. in the Magento back-office everywhere ElasticSuite is impacting, it's done by the es-logo.svg image here : https://github.com/Smile-SA/elasticsuite/tree/2.11.x/src/module-elasticsuite-core/view/adminhtml/web/images

New logo will be shared by our internal sharing system