Add a self user agent plugin

Fix vimeo

Just like with the "ip" query, duckduckgo gives the server's
information with the "user agent" query.
This corrects this behavior by adding a plugin based on self_ip.py plugin.

Update Dockerfile.

- Install new packages needed to deploy search
- Optimize dockerfile for more docker deamon caching
- Pin a python2.7 base image.

[enh] google engine : parse map links and more

Allow use of chars as € in currency converter

bing_images & www1x engines use https connections

fix little bug inside settings, improve oscar template

Bing news based on RSS output

New feature : language per search engine !

Adds engines : Youtube with or without API and multiple Qwant

Add startpage as an autocompleter engine

google engine

implement swisscows engine

TODO: implement image engine

- Web
- Images
- News
- Social media

The API needs an API_KEY
The NOAPI doesn't have the published dates.

This allow to send request to google.* (according to the search language).
Before this commit, request in other languages than english was sent to www.google.com which was redirected to www.google.*
The PREF is still use on the www.google.com domain.