EVM Node: Add performance metrics

These metrics can be used to monitor how the node behaves in the long run, similarly to what was done in the Rollup Node. We rely on the function introduced in e9f3ad0b to decide whether or not we enable these metrics.

Manually testing the MR

Start a node, and enjoy this manual scrapping command.

watch "curl -s http://localhost:8545/metrics | grep performance | grep -v '#'"

In my case,

octez_evm_node_performance_connections 1.000000
octez_evm_node_performance_cpu_percentage 186.000000
octez_evm_node_performance_data 244.620594
octez_evm_node_performance_disk_percentage 85.000000
octez_evm_node_performance_file_descriptors 49.000000
octez_evm_node_performance_logs 0.034466
octez_evm_node_performance_mem_percentage 1.800000
octez_evm_node_performance_resident 0.588577
octez_evm_node_performance_store_irmin 239.119747
octez_evm_node_performance_store_sqlite 5.466377
octez_evm_node_performance_virtual 7.706596
octez_evm_node_performance_wasm 0.000004

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR