* add button for languages setting
* build a web module for the dashboard
- load all python module from local dir
- initialize Blueprint and Babel
* set a default key for secure cookies
* add translations to docker container
* improve translation build
- clean target erases the *.pot
- don't modify the resurt of url_for() calls
- don't translate the language description
* translate connection table, fix icon
* build relative urls for HA ingress
* fix unit test, increase coverage