data/defaults: Update swh-web configuration

Summary:
Configuration update for swh-web

I am opening that diff to swh-site as I need to update the
swh-web configuration before redeploying and I do not have
the rights to push on that repo.

Related: T952

Reviewers: ardumont

Reviewed By: ardumont

Differential Revision: https://forge.softwareheritage.org/D298