Produce metrics from json pathes

[martin-huber]

probe_httpjson_gitgroups_id{groupIndex="0"} 189
probe_httpjson_gitgroups_members{groupIndex="0", membersIndex="0", name="Hannes"} 1
probe_httpjson_gitgroups_members_age{groupIndex="0", membersIndex="0"} 37
probe_httpjson_gitgroups_members{groupIndex="0", membersIndex="1", name="Joseph" lastname="Vilimas"} 1
probe_httpjson_gitgroups_members_age{groupIndex="0", membersIndex="1"} 33
probe_httpjson_gitgroups_members{groupIndex="1", membersIndex="3", name="Martin"} 1
probe_httpjson_gitgroups_members_age{groupIndex="1", membersIndex="3"} 55

For an API like:

[
	{
	  id: 1,
	  members: [
		{ name: "Hannes", age: 37},
		{ name: "Joseph", age: 33}
	  ]
	},
	{
	  id: 2,
	  members: [
		{ name: "Hannes", age: 37},
		{ name: "Joseph", age: 33},
		{ name: "Martin", age: 55}
	  ]
	}
]

probe_probername_configuredPrefix_dynamicGeneratedPathes
probe_httpjson_gitgroups_....

Prometheus Config:

scrape_configs:
  - job_name: cloudsigma_snapshots_json
    metrics_path: /probe
    params:
	  target: http://api.com/api/json
	  module: [json]
	  //jsonPath: [objects[.*].allocated_size, objects[.*].drive.uuid]
	static_configs:
	 - targets:
	   - http://blackbox-export-url:9115

Blackbox Exporter Config:

modules:
   json:
      prober: httpjson