Debug: Add DEBUG Timestamps

[maschad]

Would like to have the option to prepend [YYYY/MM/DD - HH:mm:ss] to all debug output lines by passing in an environment variable timestamps=true to enable them or by setting this in localstorage

Originally https://github.com/libp2p/js-libp2p-logger/issues/33

[tabcat]

It looks like this is already available in debug https://github.com/debug-js/debug#environment-variables. Although the date format is slightly different.

[maschad]

That's why I had opened this issue, it's actually been discussed on debug-js but there is still an ongoing discussion on how to format output, but this exact format is desired for our library.

[achingbrain]

Closing as this is configurable via env vars as pointed out above and any extra work would not be carried out in this repo.