Change analytics queries to run sequentially

[ktuite]

Closes #1228

Makes use of runSequentially instead of Promise.all() to do multiple database queries for computing usage metrics.

What has been done to verify that this works as intended?

Why is this the best possible solution? Were any other approaches considered?

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

Does this change require updates to the API documentation? If so, please update docs/api.yaml as part of this PR.

Before submitting this PR, please make sure you have:

• run make test and confirmed all checks still pass OR confirm CircleCI build passes
• verified that any code from external sources are properly credited in comments or that everything is internally sourced

[matthew-white]

I'll let @sadiqkhoja do the review, but I had just one thought. Are we able to remove lines like this from tests of analytics now?

central-backend/test/integration/other/analytics-queries.js

Line 2148 in 63ca788

require('events').EventEmitter.defaultMaxListeners = 30;