metrics-export-role: update information

[themilchenko]

Product: metrics-export-role
Since: 0.2.0
Audience/target: customers
Root document: where to add or update documentation
SME: @themilchenko

Details

Since 0.2.0 version a few features were introduced that was forgotten to update in doc:

• Latency observation for http endpoint.
• Integration with httpd role.
• Support TLS with listen parameter.
• Integration with Graphite.

All examples and definitions can be found in README of module.

Planning checklist

• metrics.enabled option;
• write up about integration with httpd role;
• TLS with listen parameter;
• Graphite integration.