Demos - clean up logo assets in demos

[tlabaj]

Describe the enhancement or change
A clear and concise description of the request. What is the expected outcome?
There are a lot of duplicate images in the demos space. Can we add an assets directory and get the image from one place in all demos.

[MariaAga]

@tlabaj Can I be assigned on this? I think it will be good to just move any image assets to react-core/src/components/assets/ or react-core/src/demos/assets/ depending on were the import happens

[tlabaj]

@MariaAga Yes, thanks for picking this one up.