Test web app deploy

[mmmarcos]

This could be deployed in S3 (AWS) as is the case with Parsec Sign.

The web app should be linked to the already deployed nightly server (NOTE: demo scalingo server is not auto upgraded on nightly build, the job is manually triggered from saas deploy repo).

Proposed by @vxgmichel: if we are going to deploy the web app, we might as well do it during the nightly build.

[NicoTuxx]

configuration:
app.parsec.cloud => future production
app-dev.parsec.cloud => future pre-prod