In this commit, the docker-compose file was modified to include the
`google-credentials.json` file as a secret volume. This change was made
to ensure that the necessary Google credentials are available for the
analytics service running on the `participation.sanchogov.tools`
sub-domain. Including the `google-credentials.json` file in the
docker-compose configuration is crucial for the proper functioning of
the analytics dashboard service.

In this commit, an argument (`NEXT_PUBLIC_API_URL`) was added to the
`Dockerfile` of the analytics-dasboard service. This change is necessary
to dynamically specify the API URL that the dashboard should connect to.
By introducing this build arg, the analytics dashboard service can now
adapt to different environments, like the
`participation.sanchogov.tools` sub-domain, as part of configuring the
analytics service under one domain tree.