Add Grafana dashboard panels for scan monitoring

This commit adds dashboard panels to visualize scan metrics:

Stat panels:
- Conductor Full Scan Elapsed Time
- Conductor Scan Counts (buckets, lifecycle buckets, workflows)
- Bucket Processor Lifecycle Buckets (running total per pod)

TimeSeries panels:
- Bucket Processor Scan Progress (start time per pod)
- Bucket Processor Buckets Count (count per pod over time)

Issue: BB-740

Author: benzekrimaha