Implement Genesis utility modules

[austinabell]

The rationale for this is because the genesis utility modules (genaccounts and genutil) are designed specifically for cosmos addressing and signing. These modules need to be included to allow for a user to generate genesis configuration with accounts and collect the genesis tx with an Ethereum compatible signature (#78 implemented the key generation and signing capabilities needed for this).

Currently, the options seem to be to have the UX and functionality map to what CosmosSDK applications currently have with the included modules or create functionality to convert an Ethereum genesis JSON file to generate an Ethermint config.

The CosmosSDK functionality is to add genesis accounts, sign the tx with the daemon gentx command, then collect that signed tx to generate a genesis.json file compatible with CosmosSDK.

If the conversion from Ethereum JSON to CosmosSDK compatible JSON is intended, then the JSON file would have to be parsed to modify the config for each parameter and allocate the genesis accounts based on this, but signing and collecting this genesis tx will still have to be implemented to fit into the current flow. Because this does not add any very useful functionality it makes more sense to implement the former, but this can be revisited if wanted.

[austinabell]

This issue should be the last blocker for updating #71 since the genesis tx generation and signing is the only thing in the way of starting the chain with this anteHandler