Provide all the libzim javascript bindings

[mossroy]

(transferred from kiwix/kiwix-js#768)

Like it is done for python : https://github.com/openzim/python-libzim/
Apart from generating the libzim.a file (kiwix/kiwix-build#548), the CI should also provide all the javascript bindings that allow to call it.

A few bindings are already in the demo_file_api.cpp file of this repo.
This file should be renamed, and completed with all the libzim APIs.
It should also be compiled in the CI, IMHO.

It would allow the libzim to be used in different javascript projects (kiwix-js of course, but maybe mwoffliner or some other ones)

[mossroy]

The easiest way (to begin with) would be to generate the wasm file (with its prejs/postjs contents), ready to be used in a webworker context (like it's already done here).

I don't know if it's necessary (and possible) that this repo only generates a wasm file (without the prejs, postjs and webworker context), that could be used in different contexts. I did not investigate that

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be now be reviewed manually. Thank you for your contributions.

[kelson42]

@Jaifroid This an issue, I though this has finally be solved?!

[Jaifroid]

It's still an issue: the only bindings ever done were the basic ones. It's something that I would need help with, as I don't know C`++ or the libzim APIs. What we currently have is getting content from the ZIM by path, doing an article count, and doing Xapian search, if I remember rightly.