Add ability to import different keystore/private key formats for createconfig call

[pstehlik]

Currently, the command centrifuge createconfig expects the wallet in JSON Keystore format. It would be great to have the ability to import (and then convert) a raw private key as well. Might make it much simpler for some first time users who don't have geth installed in order to generate their initial wallet (which they then might fund from Metamask or something else not so command-line-heavy).

[sanidhayarora]

Hi, can i work on this issue?

[pstehlik]

Thanks for checking in. We'll have to spec it out a bit more before it would be ready for an outside contributor. Hoping to get to that in the next few days.