Metrics dashboard

[mszarlinski]

This PR is related to #7 and introduces the following features:

1. Spring Boot metrics published to Prometheus
2. MeteredDomainEventPublisher wrapper that counts published events
3. Starting library application, Prometheus and Grafana with docker compose
4. Feeding database with initial data when running with local profile
5. New endpoint for placing a hold: POST /holds. From now on you can generate business events by placing and canceling a hold

I am open for feedback and discussion :)

Below you can see screenshots from Grafana dashboard:

[pilloPl]

great job!