Improve language auto-detect for batch requests with multiple languages

Mention Argos in leading paragraph

One of the first things that people will probably want to know about this
project is how the actual translation work. Therefore, add mention of
Argo to the leading paragraph of the readme.

fix(default_values.py): remove debug print

docs(readme): add info about env vars

Added Argos Open Tech mirror

Add env support

Signed-off-by: euberdeveloper <euberdeveloper@gmail.com>

Add min-height to main app

Adds min-height: 80vh; The footer will stay always at the bottom on big screens and looks normal on mobile devices.

update pyicu  to fix build on macos

Right now brew installs icu4c 69.x which pyicu only supports from 2.7

Add downArrow to select language + fix select language problem with small screens

Logo, move LibreTranslate org