Migrate tasks to Faktory

[fennifith]

Currently, tasks are passed through a TaskRequest/Result table in postgres. (partially completed by #4, in faktory-migration)

We'd like to migrate to faktory instead. This involves:

• Create a docker container for local dev to run a faktory server
• Configure NodeJS worker/ to connect to Faktory using its NodeJS library
• Edit the Kotlin server (TaskService) to push jobs to Faktory instead of Postgres
• Write to separate tables for each job type (e.g. CREATE TABLE UrlMetadata) to write results into
• Remove the now-unused "Task*" postgres tables/code
• Create a Fly.io service configuration for Faktory
• Set up Faktory's web UI to be accessible from Fly.io?