feat: pre-deployed erc20 gas token

[leovct]

Description

Allow to use a pre-deployed ERC20 gas token.

Now we support three different configurations related to the gas token:

1. Don't use a gas token (default behaviour)

args:
  gas_token_enabled: false

2. Use a gas token but automatically deploy the contract on L1.

args:
  gas_token_enabled: true

3. Use a gas token and use the provided contract address.

args:
  gas_token_enabled: true
  gas_token_address: "0xCONTRACT_ADDRESS"

Tests

The following tests should be added to the CI:

• Use a gas token but automatically deploy the contract on L1.
• Use a gas token and use the provided contract address.

🚨 Unfortunately, it broke all the cdk tests related to gas token... I fixed the tests on my fork and will push an upstream PR once this PR gets merged.

References (if applicable)