DOTNET-5968 Add extra information to /metrics endpoint (SUP-5887)

[mattwarren]

https://contrast.atlassian.net/browse/DOTNET-5968

From https://contrast.atlassian.net/browse/SUP-5887?focusedCommentId=492466:

Create a new release of the Agent Operator with the following:
- Additional information exposed via the /metrics endpoint (still researching how we do some of this)
  - Native cpu/memory usage of the Operator
  - Pod cpu/memory limits from the K8s API
  - "IsLeader" flag
- Extra logging to diagnose the uncaught .NET Exception that is causing the restart
  - We think it’s an "Out of Memory" exception, but need to confirm this
  - Currently dmesg just shows `.NET ThreadPool[1547673] general protection fault ip:7f54186ec50f sp:7f539e2d0c60 error:0 in libc.so.6`

[mattwarren]

I've tested this locally and it looks okay:

// http://localhost:5001/api/v1/metrics
{
  "UptimeSeconds": 94.9121163,
  "Resources.DaemonSetResource.NamespacesCount": 1,
  "Resources.DaemonSetResource.ResourcesCount": 1,
  "Resources.DeploymentResource.NamespacesCount": 1,
  "Resources.DeploymentResource.ResourcesCount": 1,
  "Resources.SecretResource.NamespacesCount": 1,
  "Resources.SecretResource.ResourcesCount": 1,
  "Resources.PodResource.NamespacesCount": 1,
  "Resources.PodResource.ResourcesCount": 9,
  "Resources.Global.NamespacesCount": 1,
  "Resources.Global.ResourcesCount": 12,
  "Injected.PodsCount": 0,
  "Performance.Gen2GCCount": 0,
  "Performance.Gen1GCCount": 0,
  "Performance.PercentTimeinGCsincelastGC": 0,
  "Performance.WorkingSet": 141,
  "Performance.CPUUsage": 0,
  "Performance.AllocationRate": 5149584,
  "Performance.Gen0Size": 292784,
  "Performance.MonitorLockContentionCount": 6,
  "Performance.NumberofMethodsJitted": 10935,
  "Performance.Gen1Size": 10442536,
  "Performance.ILBytesJitted": 690771,
  "Performance.POHPinnedObjectHeapSize": 212128,
  "Performance.GCHeapSize": 20,
  "Performance.NumberofAssembliesLoaded": 189,
  "Performance.GCCommittedBytes": 29,
  "Performance.ExceptionCount": 290,
  "Performance.NumberofActiveTimers": 26,
  "Performance.ThreadPoolQueueLength": 0,
  "Performance.LOHSize": 567672,
  "Performance.ThreadPoolThreadCount": 6,
  "Performance.TimespentinJIT": 635.7404000000001,
  "Performance.GCFragmentation": 3.630939892821068,
  "Performance.ThreadPoolCompletedWorkItemCount": 543,
  "Performance.Gen0GCCount": 0,
  "Performance.Gen2Size": 576,
  "IsLeader": "True"
}

[mattwarren]

Added details metrics with the Process. prefix, the new output is below.
Note that I tested this in a local cluster with replicas: 2 and the IsLeader value works as expected, i.e. one Pod has "IsLeader": "True" and the other "IsLeader": "False"

{
  "Injected.PodsCount": 0,
  "Performance.AllocationRate": 1552280,
  "Performance.CPUUsage": 0,
  "Performance.ExceptionCount": 48,
  "Performance.GCCommittedBytes": 0,
  "Performance.GCFragmentation": 0,
  "Performance.GCHeapSize": 39,
  "Performance.Gen0GCCount": 0,
  "Performance.Gen0Size": 0,
  "Performance.Gen1GCCount": 0,
  "Performance.Gen1Size": 0,
  "Performance.Gen2GCCount": 0,
  "Performance.Gen2Size": 0,
  "Performance.ILBytesJitted": 875597,
  "Performance.LOHSize": 0,
  "Performance.MonitorLockContentionCount": 8,
  "Performance.NumberofActiveTimers": 18,
  "Performance.NumberofAssembliesLoaded": 179,
  "Performance.NumberofMethodsJitted": 13013,
  "Performance.PercentTimeinGCsincelastGC": 0,
  "Performance.POHPinnedObjectHeapSize": 0,
  "Performance.ThreadPoolCompletedWorkItemCount": 534,
  "Performance.ThreadPoolQueueLength": 0,
  "Performance.ThreadPoolThreadCount": 6,
  "Performance.TimespentinJIT": 16.364399999999932,
  "Performance.WorkingSet": 164,
  "Resources.DaemonSetResource.NamespacesCount": 1,
  "Resources.DaemonSetResource.ResourcesCount": 1,
  "Resources.DeploymentResource.NamespacesCount": 2,
  "Resources.DeploymentResource.ResourcesCount": 2,
  "Resources.Global.NamespacesCount": 2,
  "Resources.Global.ResourcesCount": 16,
  "Resources.PodResource.NamespacesCount": 2,
  "Resources.PodResource.ResourcesCount": 11,
  "Resources.SecretResource.NamespacesCount": 2,
  "Resources.SecretResource.ResourcesCount": 2,
  "UptimeSeconds": 315.2051509,
  "Process.WorkingSet64": 169861120,
  "Process.MinWorkingSet": 0,
  "Process.MaxWorkingSet": 536870912,
  "Process.PeakWorkingSet64": 169861120,
  "Process.PrivateMemorySize64": 253161472,
  "Process.VirtualMemorySize64": 6317158400,
  "Process.PeakVirtualMemorySize64": 6334402560,
  "Process.PagedMemorySize64": 0,
  "Process.PeakPagedMemorySize64": 0,
  "Process.NonpagedSystemMemorySize64": 0,
  "Process.TotalProcessorTime": "00:00:05.2300000",
  "Process.UserProcessorTime": "00:00:04.9100000",
  "Process.PrivilegedProcessorTime": "00:00:00.3200000",
  "Process.Thread": 19,
  "Process.Modules": 151,
  "IsLeader": "False"
}