attempt `newGameUser` jobs 3x w/ 60s b/t each attempt

Fixes #140.

Does not fix https://github.com/LearnersGuild/game/pull/558, which is a much bigger lift and will require significant refactoring.

Overview

We use bull for our job queues, which by default, do not automatically retry. What this means is that if something operational causes the job to fail (e.g., the database is in the middle of a restart, etc.), we just give up.

We should retry jobs to make the system more resilient. That's what this PR is about.

In addition, to help us with debugging, I've added matador to the /job-queues route of game so that we can see the status of the various job queues.

Data Model / DB Schema Changes

N/A

Environment / Configuration Changes

npm install is required to install matador

Notes

Different types of jobs may need different settings WRT retries. For example, some jobs may do only database-related stuff, while others might invoke remote APIs. When configuring the jobs to retry, I've used the following "rules" to determine how quickly the job should retry:

if the job hits an external API, it will wait 60s
if the job hits an internal API (such as creating a channel on our echo server), it will wait 10s
if the job doesn't hit any APIs, it will wait 5s before retrying

By default, all jobs will retry 3 times before giving up.

LearnersGuild / idm