test: Use test token faucet

[teogeb]

Removed KeyServer, using generateWalletWithGasAndTokens() instead of fetchPrivateKeyWithGas()

TODO:

• add e.g. { tokens: boolean } to control whether to mint tokens
• maybe also { gas: boolean } to control the gas transfer (if both booleans are false, this is just an alias to fastPrivateKey())
• then remove fetchPrivateKeyWithGas()

Benchmark

Seems that this decreases test runtime. But run tests multiple times to ensure that. Current results:

• total runtime: 2903s -> 2825s
• slowest, i.e. node-e2e: 367s -> 346s

Other changes

Commit 8ee7a8a could be a separate PR

Moved generateWalletWithGasAndTokens() to test-utils. That commit could be a separate PR 5d68316

Note

setupOperatorContract() needs generateWalletWithGasAndTokens() because that method is in theory "production code" and generateWalletWithGasAndTokens() is test code. In practice setupOperatorContract() is test code -> we don't need this hack if we refactor setupOperatorContract() to be a test utility (i.e. not in operatorContractUtils)

Future improvements

Maybe retry() logic is not needed in generateWalletWithGasAndTokens()?