Fix duplicate /api in path

name: Hotfix
about: Quick bugfix with very localized and low impact changes.

Description

On salons-test.paris.inria.fr, the frontend routes incorrectly to the api.

Steps to reproduce

• Go to salons-test web site
• Try to log in (superdsi)

Result

A popup appears with "No authorized".

You can see in logs:

172.17.0.1 - - [25/Jan/2021 18:32:13] "POST /api/api/signin HTTP/1.0" 404 -

Expected result

You are logged.

In logs, you see:

172.17.0.1 - - [25/Jan/2021 18:32:13] "POST /api/signin HTTP/1.0" 200 -