[Extension] Glue HttpService with MetricService

[YunaBraska]

Description

The MetricService is one of the default example service extensions. It covers only simple metrics like counter, gauge and timer and consumes metric update events

Acceptance Criteria

• MetricService endpoint URLs are configurable for prometheus, influx, dynatrace (Add configs here), wavefront
• MetricService response to HttpRequest events for each configured URL - Url Examples:
  • base url: /some/url
  • /prometheus = /some/url/prometheus
  • /influx = /some/url/influx
  • /dynamo = /some/url/dynamo
  • /wavefront = /some/url/wavefront
  • custom prometheus url : /my/actuator/prometheus
• Cover the HTTP connection to the Metric Service with tests.