Customize job name for multiple KeyCloak clusters on the same Prometheus PushGateway

[guerricmerleHUG]

Motivation

#100

What

This Pull Request introduces a new system environnment variable PROMETHEUS_GROUPING_KEY_JOB to override default "keycloak" job name.

Why

Being able to define our own custom PROMETHEUS_GROUPING_KEY_JOB in order to separate indicators of different clusters

How

Add new system env PROMETHEUS_GROUPING_KEY_JOB

Verification Steps

Add the steps required to check this change. Following an example.

1. Build the code
2. Copy the artifact into $KC/standalone/deployments
3. set system var env to PROMETHEUS_GROUPING_KEY_JOB=keycloak_cluster_A
4. Make sure the metrics logger is turned on
5. Play with Keycloak a bit
6. Look at the following url: "$KC/auth/realms/master/metrics", job name is equals to keycloak_cluster_A

Checklist:

• Code has been tested locally by PR requester
• Changes have been successfully verified by another team member

Progress

• Finished task
• TODO

[semangard]

@pb82 : is-it possible to check this PR please ?

[pb82]

Yep, seems like a small enough change. I'll try to get it in asap.