Configure Sentry for web API and web site

EPIC: #512

• As a maintainer of the DBnomics platform
• I want to see error details in a central place
• in order to improve platform resilience and gain time while investigating breakdowns

Tasks

• create an account on https://sentry.io/
• create projects for web API and web site on Sentry
• add Sentry client to web API
• add Sentry client to web site in server-side (server.js with Sentry Node JS client)
• add Sentry client to web site in client-side (find HOWTO)
• ensure e-mail alerts are sent
• optional: add Sentry errors metric to Prometheus + Grafana not clear