Enhance yorc metrics (especially operation execution) to make them more "parseable"

[fcdenos]

Is your feature request related to a problem? Please describe.
The yorc metrics returned by /yorc_metrics URL could be more usable if we could have another syntax than this type :
yorc_executor_operation_WXC_PERIMETRE_TIERS_HOB_SECLIN_sg_nodes_PrometheusAgent_standard_create_sum

Describe the solution you'd like
Instead of the syntax above, it would be better for automated parsing and analysis to have something like :
yorc_executor_operation{deployment=WXC_PERIMETRE_TIERS_HOB_SECLIN}{type=sg_nodes_PrometheusAgent}{operation=standard_create}_sum

[loicalbertin]

@fcdenos we plan to refactor the metrics in 4.0 cycle (see #297).
We will take advantage of the labels mechanism it will be more Prometheus-friendly.

[adidanes]

Hi @fcdenos,

Can you take a look to the PR : #569.

For the metric example that you provided, it should be identified like this:

yorc_executor_operation{Deployment="WXC_PERIMETRE_TIERS_HOB_SECLIN", Node="sg_nodes_PrometheusAgent", Name="standard_create"}

[fcdenos]

Hi @adidanes,
It seems to fulfill our needs, thanks !