Add ops metrics

[davidd8]

Add some system operational metrics to monitor the status of the Autoretrieve service, which can help identify scaling issues and help with capacity planning:

• [ ] Uptime graph (how often is the service restarting)
• [ ] Storage usage (ensure pruning is working)
• [ ] Bandwidth usage (check if we're maxing out on connections or bandwidth, etc.)
• [x] Memory and Process Usage (can the machine handle the request load)

cc @hannahhoward @kylehuntsman

[hannahhoward]

@kylehuntsman can you check off which of these are done?