Add min. 1 new KPI to the metrics engine

[codeDavidLopez]

User story

1. As a user
2. I want / need a new KPI (not yet available)
3. So that more information about the network and ledger is available

Acceptance criteria

• minimum 1 new KPI defined (a information not yet available), suggestions here: https://github.com/amosproj/amos2022ss06-idunion-blockchain-dashboard/tree/main/indy-node-monitor/fetch-validator-status#extracting-useful-information
• New KPI calculated with metrics engine
• New KPI stored in Prometeus.io
• New KPI available for the Grafana Dashboard

Feature DoD

• Feature has been fully implemented
• All acceptance criteria were met
• All tests are passing
• No known errors
• Documentation updated
• Bill of materials updated

Sprint Release DoD

• Feature has been fully implemented
• Feature has been merged into the mainline
• All acceptance criteria were met
• Product owner approved features
• All tests are passing
• Peer code review passed
• Developers agreed to release
• Documentation updated
• Bill of materials updated

[A-Sandrini]

not finished in sprint 6

[A-Sandrini]

re-estimation = 8