Collect count of secrets

[shaun-nx]

Proposed changes

This change updates the telemetry collector to count the number of Secret resources managed by the Ingress Controller.
This change makes updates to our local Secret store to allow access to the secret reference map. This ensures we only count secrets that are watched and managed by NIC (i.e. it will exclude secrets that we explicitly ignore and secrets that are not in a watched namespace)

Additional changes

• Updated comments in values.yaml
• Renamed variables and structs in main.go and update some comments

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork