Prometheus Metrics addon

Adding prometheus metrics to framework.

• To enable provider use prometheus.New() method in providers list.
• New endpoint is available by default config at /metrics path with GET call. Can be configured by config variable called ENDPOINT_METRICS.

Bugfixes, code formatting, go vet fix

v0.1.0

Fixed issues reported by vet, linter and fmt

Initial release

This is the initial release covering:

• Service providers skeleton
• Configuration loader
• Multiple default configuration providers: cmdconfigprovider, envconfigprovider, yamlconfigprovider