R1:686c02d54a7a

Add a "memory.hint" parameter to Aphlict

Summary:
Ref T10696. By default, `node` uses 1.5GB, which is enormous overkill for this service and can crowd out other services if it's running next to things like a database on the same host.

Provide a configuration option to adjust it via `--max-old-space-size` and default to 256MB. It only seems to need about 30M locally, so this should be plenty of headroom.

Test Plan:
Ran `bin/aphlict debug`, things seemed OK.

It takes a long time (days?) to grow to 1.5GB…