Metrics support at the application configuration level

[malaskowski]

Context
Enable metrics configuration from the Knot.x configuration.

Describe the solution you'd like
Vert.x enables metrics via SPI (there are numerous implementations like Dropwizard or Micrometer).
Enabling the metrics is configured when the Vert.x instance starts (that's the only way to pass the MetricsOptions to the Vert.x instance). One way to enable metrics is actually pas those options via command line, however this is not very intuitive way.
A one lot better would be to pass all necessary configs (including specific ones for the metrics SPI provider) via HOCON configuration, e.g.

metrics {
  enabled = true
  config {
    name = micrometer
    config {
      //specific config
    }
  }
}

Describe alternatives you've considered
There is actually an alternative implemented, which is Knot.x Dropwizard Metrics module. However, it is kind of hacky, and assumes that metrics are already enabled and some Dropwizard registry exists.

Additional context
It would be great if the configuration enables to run Hystrix Dashboard that shows current circuit breaker status.