Add account CLI

[dapplion]

Adds an acount CLI feature-pair with lighthouse's account CLI.

How to test

Normal usage flow of the account CLI could be:

lodecli account wallet create --name wallet1 --passphraseFile wallet1.pass

lodecli account wallet list

lodecli account validator create --name wallet1 --passphraseFile wallet1.pass --count 1

lodecli account validator deposit --validator all --eth1Http http://your.unlock.node:8545

Available commands

Summary of the command hierarchy, use --help at any level to get full details and options.

account
  validator
    create    Creates new validators from an existing EIP-2386 wallet...
    deposit   Submits a deposit to an Eth1 validator...
  wallet
    create    Creates a new HD (hierarchical-deterministic) EIP-2386 wallet
    list      Lists the names of all wallets

Directory structure

All major directories are one level deep of the global rootDir path. This account directory structure is very similar to ethdo and ighthouse's, expect that this one mixes account data with db data.

.lodestar/
├── keystores
│   └── 0x871cb1c0b1e6b67473003ccfbdf9532d3b0d29bf51b07df6a3fae2ba25526d18e67a119babd44aa3b22b9bc4ef16f71f
│       ├── eth1-deposit-data.rlp
│       ├── eth1-deposit-gwei.txt
│       └── voting-keystore.json
├── secrets
│   └── 0x871cb1c0b1e6b67473003ccfbdf9532d3b0d29bf51b07df6a3fae2ba25526d18e67a119babd44aa3b22b9bc4ef16f71f
├── validator-db
│   └── 0x871cb1c0b1e6b67473003ccfbdf9532d3b0d29bf51b07df6a3fae2ba25526d18e67a119babd44aa3b22b9bc4ef16f71f
│       ├── 000003.log
│       ├── CURRENT
│       ├── LOCK
│       ├── LOG
│       └── MANIFEST-000002
└── wallets
    └── 05939fbd-923a-4559-b41f-2e43ad8fd80b
        └── 05939fbd-923a-4559-b41f-2e43ad8fd80b

Other minor changes

• Clean CLI export style to prevent the use of 'as any' casting. Type-safety = 😄
• CLI now prints help when no command is provided and it's required.
• CLI now recommends possible command names if no command is matched
• Added welcome message in help of the root command

🌟 Lodestar: Ethereum 2.0 TypeScript Implementation of the Beacon Chain

Next steps

• Provide more options to broadcast a deposit data, i.e. connect to Metamask, IPC, Ledger?
• Support non-HD wallets
• Add tests

[wemeetagain]

Looks really good, this is great work.
just minor comments and questions