Implement a benchmark for the ledger operations

[dnadales]

As a preliminary step toward identifying the node's performance bottlenecks, we should elaborate a benchmark that measures the time the ledger operations consume while applying blocks in the mainnet chain. These operations are:

• forecasting
• header ticking
• header application
• block ticking
• blocks application

Use the db-analyser to create a new type of analysis that measures the time these operations take. Use the output of these measurements to write a script that plots the results.

[dnadales]

@nfrisby did the bulk of the implementation in https://github.com/input-output-hk/ouroboros-network/pull/4014. We need to drive this home, and a possible way of doing this is proposed in this comment.