Reduce size of replayWorker by removing wombat and wombat workers

[Jaifroid]

Following openzim/warc2zim#143, it might be better to include our own copy of wombat and wombat workers as a dependency in this Repo (and downstream in the PWA), rather than relying on the version embedded in sw.js / a.k.a. replayWorker.js. At build time, terser complains that it had to deoptimize the style of replayWorker because it is larger than 500KB. It seems wasteful that it includes an entire copy of wombat (minified) inside it.