introducing micrometer/prometheus metric collection

README.md

docker-compose.yml

docker/prometheus/Dockerfile

docker/prometheus/prometheus.yml

pom.xml

spring-petclinic-api-gateway/pom.xml

spring-petclinic-customers-service/pom.xml

...mework/samples/petclinic/customers/web/OwnerResource.java

...ramework/samples/petclinic/customers/web/PetResource.java

...work/samples/petclinic/customers/web/PetResourceTest.java

spring-petclinic-vets-service/pom.xml

spring-petclinic-visits-service/pom.xml

...framework/samples/petclinic/visits/web/VisitResource.java

...ework/samples/petclinic/visits/web/VisitResourceTest.java