Feature/ethers v6

[PierreJeanjacquot]

ethers v5 -> v6 migration:

Ethers have been upgraded to v6 without changing the iexec SDK API
Under the hood we have the following changes

• extraction of plain objects from ethers proxies (formatEthersResult)
• wrapping of bigint used by ethers v6 into BN exposed by iexec
• adaptation of ethers error messages extraction
• adaptation of events extraction from transaction receipts

Misc:

• due to a bug in ganache affecting ethers v6 and the project being sunsetting, ganache is temporarily replaced by openethereum client in tests, this also reduces the number of services running for the tests
  • ⚠️ because "instamine" does not exist in the openethereum client, test execution time increased by 50%
  • openethereum is also sunsetting and is planned to be replaced by neithermind (current client used by iExec)
• EIP1559 support for wallet sweep
• typos fix

TODO:

• find a suitable "instamine" replacer for ganache (asap)
• replace openethereum by neithermind in tests (asap)
• use native bigint instead of BN (next major release)

[SeddikBellamine]

Minor wording changes