Unable to fund relayer when using rootchain originated native token

[Stefan-Ethernal]

Description

This PR introduces the addGenesisBalance function on the CustomSupernetManager and integrates those changes in the Edge. It enables genesis accounts to lock root chain-originated Supernets native tokens on the RootERC20Predicate and be premined with the exact same amount of native tokens in the genesis time on a Supernets. This is especially significant for relayer nodes, because they are executing bridge transactions. Without this change, it was not possible to execute any bridge transaction with non-zero gas price transactions, which is the case for the London hard fork being enabled.

These commands were added:

1. bridge mint-erc20 command - mints ERC20 tokens to specified addresses. It has these flags:
   --addresses - list of addresses for which ERC20 tokens should be minted (separated by a coma).
   --amounts - list of amounts of ERC20 tokens that should be minted to given addresses (separated by a coma).
   --erc20-token - address of the ERC20 token that should be minted.
   --private-key - private key of the ERC20 token deployer, since only token deployer can mint tokens.
   --jsonrpc - json RPC url to a node on chain on which mint transactions are sent.
   Please note that addresses and amounts flags need to be the same length.
2. rootchain premine command - only used for non-mintable native ERC20 tokens on bootstrap of a Supernet. It locks the specified amount of native tokens on the RootERC20Predicate. Those tokens will than be premined in the genesis time on a Supernet, as described eariler. Each account that wants to have some non-mintable native ERC20 token premined on a supernet, needs to call this command itself, meaning that each validator, each relayer node, and any other node that wants to have some native ERC20 balance on Supernet from the genesis (in case of non-mintable token), needs to do this command.
   It has these flags:
   --data-dir - the directory for the Polygon Edge data if the local FS is used.
   --config - the path to the SecretsManager config file, if omitted, the local FS secrets manager is used.
   --private-key - hex-encoded private key of the account which executes command.
   --supernet-manager - address of the CustomSupernetManager contract on root.
   --erc20-token - address of the native root ERC20 token.
   --root-erc20-predicate - address of the RootERC20Predicate contract on root.
   --amount - amount of tokens to be premined.
   --jsonrpc - json RPC url to a node on root chain on which premine transactions are sent.
   Please note that --data-dir, --config and --private-key flags are mutually exclusive. The account who is calling the premine command needs to have that amount of native root ERC20 tokens. You can use the mint-erc20 command to mint him some before he premines.

Changes in deployment of a Supernet if non-mintable ERC20 native token is used

After the validators are whitelisted, registered and do the initial staking, premine to at least the relayer nodes have to be done as well. This should be the last step before the supernet command.
Here we can simply call mint-erc20 command to mint him some tokens first:

    $ polygon-edge bridge mint-erc20 \ 
       --erc20-token {address_of_native_root_erc20_token} \
       --private-key {hex_encoded_private_key_of_token_deployer} \
       --addresses {address_of_relayer_node} \
       --amounts {ammount_of_tokens_to_mint_to_relayer}

After this is done, relayer node needs to call the premine command:

    $ polygon-edge rootchain premine \ 
       --erc20-token {address_of_native_root_erc20_token} \
       --root-erc20-predicate {address_of_root_erc20_predicate_on_root} \
       --supernet-manager {address_of_CustomSupernetManager_contract_on_root} \
       --private-key {hex_encoded_private_key_of_relayer_node \
       --amount {ammount_of_tokens_to_premine}

After that, supernet command is called, which finalizes the stake and premined tokens on root, and signals that Supernet nodes can be started.

IMPORTANT: If non-mintable native ERC20 token is used, a custom reward token must be provided to genesis command through the -reward-token-code flag. (user provides hex encoded byte code of the custom ERC20 reward token). This is done because since non-mintable native ERC20 token originates on root, we can not just mint rewards on L2 in this case.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually