[docs] provide elasticsearch document structure
[docs] provide elasticsearch document structure

fixes #21

leophys/libreant,insomnia-lab/libreant,leophys/libreant,insomnia-lab/libreant,leophys/libreant,ael-code/libreant,ael-code/libreant,ael-code/libreant,insomnia-lab/libreant,leophys/libreant,insomnia-lab/libreant,ael-code/libreant