feat: add trace to logs

[tshuli]

Problem

Implements tracing for (https://github.com/datagovsg/formsg-private/issues/25)

Solution

Add trace to logs using cloudflare cf-ray header. If cf-ray does not exist, trace using x-request-id header

Tests

On staging

• At the login page, key in an invalid email address abc@abc.com. Check that the value of cf-ray header is logged under trace in the server logs error message.
• Access a public form. Check that the value of cf-ray header is logged under trace in the server logs for the get request.

On localhost

• At the login page, key in an invalid email address abc@abc.com. Check that the value of x-request-id header is logged under trace in the server logs error message.
• In L25-L27 of logging.ts, replace

isDev
  ? format.combine(format.colorize(), errorPrinter(), customFormat)
  : format.json({ replacer: jsonErrorReplacer }),

with

format.json({ replacer: jsonErrorReplacer }),

Access a public form. Check that the value of x-request-id header is logged under trace in the server logs for the get request.

New dependencies

• express-request-id^1.4.1

[karrui]

lgtm

[karrui]

nit: Can we extend the namespace globally (following suggestions in this SO post, some may be outdated) so it's consistent throughout the application?

Can also be done in a different PR, since I think we need to extend request to also have req.session.user

[tshuli]

Ok! Will create issue for this and work on it

[karrui]

Out of scope for this PR, but can you help create an issue for an utility function that returns the relevant log info from a req? Seems like the ip, trace, url, header combo is repeated throughout the application :P

[tshuli]

Ok!