Pause maintenance between repos during same task

[derrickstolee]

The PauseVerb was added along with a lot of other things in #292. It creates a file storing a timestamp for marking how long to pause maintenance. As noted in #284, this was inadequate. If there are a lot of enlistments and a user runs scalar pause in the middle of iterating over those enlistments, the maintenance task will continue to run over all of those enlistments.

Now, stop before triggering a new scalar run <task> process. Modify the markdown with the details for how many maintenance tasks completed and whether or not it was halted due to a pause. Here is a formatted version of a trace event for a task during pause:

[2020-01-22 17:17:57.7293 -05:00] RunMaintenanceTaskForRepos_MaintenanceSummary 
{
"task":"loose-objects",
"UserId":"S-1-5-21-4082248826-4152932973-4176629329-1001",
"SessionId":1,
"traceMessage":"Maintenance is paused until 1/23/2020 4:14:44 AM.",
"reposInRegistryForUser":11,
"reposSkipped":11,
"reposSuccessfullyRemoved":0,
"repoRemovalFailures":0,
"reposMaintained":0,
"haltedForPause":true
}

[kewillford]

Looks good. Just a couple naming suggestions.

[derrickstolee]

/azp run microsoft.scalar

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[derrickstolee]

/azp run microsoft.scalar

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).