Add an adapted token to FeeCurrencyDirectory (e.g. USDC)

[arthurgousset]

Currently, the Anvil devchain only has cUSD as fee currency. Add an adapted token as fee currency (e.g. USDC) so the DevTooling team can use that for testing purposes.

For example, DevTooling could use it here:

it('fetches fee currency information', async () => {
    const wrapper = await kit.contracts.getFeeCurrencyWhitelist()

    expect(await wrapper.getFeeCurrencyInformation()).toMatchInlineSnapshot(`
      [
        {
          "adaptedToken": undefined,
          "address": "0x5315e44798395d4a952530d131249fE00f554565",
          "name": "Celo Dollar",
          "symbol": "cUSD",
        },
        {
          "adaptedToken": undefined,
          "address": "0x965D352283a3C8A016b9BBbC9bf6306665d495E7",
          "name": "Celo Brazilian Real",
          "symbol": "cREAL",
        },
        {
          "adaptedToken": undefined,
          "address": "0xdD66C23e07b4D6925b6089b5Fe6fc9E62941aFE8",
          "name": "Celo Euro",
          "symbol": "cEUR",
        },
      ]
    `)
  })

Source: FeeCurrencyWhitelistWrapper.test.ts

[shazarre]

Currently there are 3 tokens deployed in foundry migrations (none of them being adapted):

• Celo Brazilian Real with symbol Celo Brazilian Real
• Celo Euro with symbol Celo Euro
• Celo Dollar with symbol Celo Dollar

Would be cool if we could customise the symbols as well apart from adding an adapted token to the list, so we could have more meaningful tests.

[arthurgousset]

@shazarre and I spoke today. Quick TLDR for future reference:

1. we will add an adapted token to the FeeCurrencyDirectory. It will be an instance of StableToken.sol with 6 digits.
2. sepately, consumers of the devchain (e.g. the CLI and SDK test suites) can freely modify symbols and FeeCurrencyDirectory settings by impersonating the Governance contract (or whichever address is the owner of the contract). For example, using anvil_impersonateAccount to "Send transactions impersonating an externally owned account or contract."