Project structure is a mess, needs tidying up

[fabianmurariu]

• rename raphtory-storage to raphtory-demo
• rename examples to demo
• move python notebooks and random python files that use raphtory in demo
• move all things rust that use the rust-api in raphtory-demo
• move all python packages in python under a sub-package called demo (so lanl, netflow, graph500) can be accessed in python via raphtory.demo

examples is a well defined concept in rust, we should use the naming only for rust examples