How to launch a dummy network with custom settings and initial coins & rolls repartition

• get a private key and associated public key and address (see wallet_generate_private_key command), these will be referenced as PRI PUB and ADR
• replace massa-node/base_config/initial_rolls.json content with

{
    "ADR": 100
}

• replace massa-node/base_config/initial_ledger.json content with

{
    "ADR": {
        "balance": "250000000"
    }
}

• replace massa-node/base_config/initial_sce_ledger.json content with

{
    "ADR": 250000000
}

• add or replace massa-node/config/staking_keys.json

[
  "PRI"
]

• Then do cargo run --features sandbox in massa-node folder