Use optional chaining to optimize logging

[dapplion]

Optional chaining only runs code at the next step of a property chain if it's defined. We could use this property to prevent running debug code with minimal syntax boilerplate. For example:

function forever() {
  while (true) {}
}
const logger = {}

logger.debug?.(forever())

A more realistic example would look like

logger.debug?.("Some data", {
  root: expensiveComputation(data)
})

And we set logger.debug = undefined if logger level is greater than debug

[dapplion]

Looked into implementing this and the semantics are ugly in practice. I've also reviewed all statements under info log level and there's nothing too expensive, 99% are string template-ing and plain objects which are very cheap to instantiate. Given that the logger bleeds into almost every module of the lodestar namespace I don't think the pros are worth to cons