Clean up node arguments

The argument handling in [`Ouroboros.Consensus.Node`](https://github.com/input-output-hk/ouroboros-network/blob/master/ouroboros-consensus/src/Ouroboros/Consensus/Node.hs) should be cleaned up. There are: `RunNodeArgs`, `NodeArgs`, `DiffusionArguments`, `ChainDbArgs`, ... :exploding_head:.

We should strike a balance between:
* Simple: keeping things as simple as possible for its main user, i.e., `cardano-node`. No footguns, good defaults, minimal number of arguments to provide.
* Re-usability: the ThreadNet tests should be able to use the same `run` function (#2472)
* Power: allow overriding them in `cardano-node` when necessary, e.g., changing the cache parameters without having to recompile the consensus layer.