Custom dev chain presets

[keorn]

Closes #4494
Seems to work as expected, all transactions get included.

[rphmeier]

Seems to override user-specified CLI options? Defaults are good but restricting freedom isn't

[keorn]

Docs will contain a warning that --chain dev is a special preset. Otherwise per Engine defaults would be needed, which would require larger changes to the current setup.

[rphmeier]

(logged as separate issue)

I think this might make sense to do as "preset" configs that could come bundled with Parity so we don't have to mess around with ugly if-else stuff. So you could just run parity preset dev == parity --chain dev ... but overidden with any following flags.