wrapper script for building snapshots

[flyingzumwalt]

As a person who wants to build snapshots, I want to build a snapshot for a specific language by

• cloning this repo
• running a single script with a simple command (just providing the language code)

Completion state:

This repository provides a script that takes one required argument: the language code of the snapshot you want to build.
Based on that argument and the info in this repo, it

• pulls from kiwix
• unpacks the dump
• modifies the dump
• writes the result to ipfs
• reports the resulting hash

[Kubuxu]

Dependencies we need for this to happen:

• rust or built extract_zim (distributing binaries is always problematic)
• ipfs daemon running

Would those dependencies be ok with you @flyingzumwalt ?

[lidel]

I believe this was closed by #77. One can now build the latest snapshot via

$ ./mirrorzim.sh --languagecode=cu --wikitype=wikipedia