LibreJS support

Fix `languages` reload

As this object can be updated from outside its own module, the module should be imported and
used instead.

Relates to https://github.com/uav4geo/LibreTranslate/issues/54

Add option --load-only to set available languages

The user will not have to install language packages from "argos-translate" that he/she has no use for.

use polyglot for language detection and transliteration

Updated Argos Translate to 1.1.4

- https://github.com/argosopentech/argos-translate/pull/43

-> e.g. if the source language is Russian, argostranslate expects a
cyrillic text

Include language models into Docker image

-> this allows the direct offline usage of the Docker image

Add .net language binding

Added link to node.js translate

https://github.com/franciscop/translate

Include reverse proxy instructions

fix static package_data for offline mode

package_data 'static/*'  won`t include sub directories so offline mode would result in 404 for static resources under js, css, fonts