Add batch processing to improve performance

[dignifiedquire]

In reference to my comment here, ipfs/notes#2 (comment) I tried to add some parallelized batch processing which has improved resource usage and performance drastically for me.

cc @bengl

[davglass]

@dignifiedquire Looks like you forgot to add the async module to the package.json so the build failed. Can you add that and make sure that all of the current tests pass? Maybe even adding in more? Thanks! 🍻

[dignifiedquire]

@davglass uups sorry about that :( should be all good now. The current tests are passing now, not sure how to add a good test for this though. If you have any suggestions I'm happy to write one.

[daviddias]

Been using this PR and it is golden! :D

[davglass]

I'll let @bengl handle this since he's been running this and registry-static for me for a while. It's his call 😄