Improve annotations based scraping for helm

[cyriltovena]

This PR introduces annotations to configure scraping per profile type.

For example:

metadata:
  annotations:
    profiles.grafana.com/memory.scrape: "true"
    profiles.grafana.com/memory.port: "8080"
    profiles.grafana.com/cpu.scrape: "true"
    profiles.grafana.com/cpu.port: "8080"
    profiles.grafana.com/goroutine.scrape: "true"
    profiles.grafana.com/goroutine.port: "8080"

will scrape the memory, cpu and goroutine profiles from the 8080 port of the pod.

[cyriltovena]

The build is failing because we need to tag 0.5 with the new prometheus lib. But we can still merge this one.

[simonswine]

This seems to work for me. Thanks for getting this wall of YAML in 😂

LGTM

[cyriltovena]

Thanks I'll merge and cut 0.5 :)