Working version of queue length metric

[SDxKeeper]

Based on PR #18 which got stuck few months ago.

Debugged and real life-tested version of the azure_devops_agentpool_queue_length metric

[mblaschke]

Can you also do a git fmt on all files?

[SDxKeeper]

Can you also do a git fmt on all files?

Done, did go fmt on all .go files in this PR.

[frek818]

Hello @SDxKeeper, I'm trying to make use of the azure_devops_agentpool_queue_length metric but it doesn't appear in my list of metrics. Do I have set some option to make this metric appear. This is how I am currently running the exporter.

I'm using the latest version:

{"file":"main.go:41","func":"main","level":"info","msg":"starting azure-devops-exporter v21.8.1 (f84fc36; go1.17; by webdevops.io)"}

docker run -ti -p8080:8080 webdevops/azure-devops-exporter --azuredevops.organisation=myorg --azuredevops.access-token=mytoken

Thank you