Update node implementation

Our substrate node [implementation](https://github.com/joystream/joystream/tree/master/node) is based on the substrate [node-template](https://github.com/paritytech/substrate/tree/master/bin/node-template). Over time as we updated version of substrate we use, some pieces came from node-template and other from [node](https://github.com/paritytech/substrate/tree/master/bin/node).

It is now a bit disorgranised and missing some useful tests.

Proposal
Update 'node/` folder and cargo package layout to match with substrate node to make updates in future easier to maintain.

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