• Add derailed_benchmarks gem for performance benchmarking
• Clean up requires throughout code (no performance change, but sidekiq plugins get required via the Gemfile, so manual require in each worker file has no effect)
• Benchmark showed high number of allocations from ruby-oembed gem. Reimplemented using own service class.
• Do not require TTY gems from Gemfile, require them from rake task. Reduced RAM of non-rake processes by a very small amount.

Replaced preloaded JSON-LD contexts (stored as Ruby classes) with a method that hooks into the JSON-LD document loader and caches the response of the context using Rails cache.

Benefits:

• This reduces the boot time RAM by a further ~6 MiB
• Loads any JSON-LD context using our own code and timeouts and caches it for quick retrieval
• Technically the memory requirements are the same, but those ~6 MiB are in Redis and only retrieved when needed, and can be garbage-collected after
• Supports changing contexts better than hardcoding them

Other unfixed high-memory offenders:

• Chewy (Witchcraft memory allocation toptal/chewy#644) (21.4531 MiB)
• Charlock Holmes (3.0195 MiB)