DEVOPS-829 format fix for prometheus metrics

[rekibnikufesin]

Description

This PR changes the format of summary and histogram metrics as exposed by the metrics endpoint to adhere to the Prometheus metric type definitions as seen here

Prior to this change, a summary type metric would be exposed on the endpoint as two distinct metrics:

# TYPE chain_validation_count counter
chain_validation_count 397884

# TYPE chain_validation summary
chain_validation {quantile="0.5"} 199349
chain_validation {quantile="0.75"} 270883.5
chain_validation {quantile="0.95"} 460101.04999999993
chain_validation {quantile="0.99"} 641909.1200000001
chain_validation {quantile="0.999"} 1.0424829650000001e+06
chain_validation {quantile="0.9999"} 1.043075e+06

This PR updates the metric to display as:

# TYPE chain_validation summary
chain_validation {quantile="0.5"} 199349
chain_validation {quantile="0.75"} 270883.5
chain_validation {quantile="0.95"} 460101.04999999993
chain_validation {quantile="0.99"} 641909.1200000001
chain_validation {quantile="0.999"} 1.0424829650000001e+06
chain_validation {quantile="0.9999"} 1.043075e+06
chain_validation_sum some_sum_of_the_values_measured
chain_validation_count 397884

These metrics are affected by the change: chain_account, chain_account_hashes, chain_account_reads, chain_account_updates, chain_execution, chain_inserts, chain_prefetch_executes, chain_snapshot_account_reads, chain_snapshot_commits, chain_snapshot_storage_reads, chain_storage_commits, chain_storage_hashes, chain_storage_reads, chain_storage_updates, chain_validation, chain_write, client_requests_checkpoint_duration, client_requests_checkpointcount_duration, client_requests_span_duration, client_requests_statesync_duration, eth_downloader_bodies_req, eth_downloader_headers_req, eth_downloader_receipts_req, eth_fetcher_block_announces_out, eth_fetcher_block_broadcasts_out, les_client_req_rtt, les_client_req_sendDelay, les_connection_duration, les_misc_serve_body, les_misc_serve_code, les_misc_serve_header, les_misc_serve_helperTrie, les_misc_serve_proof, les_misc_serve_receipt, les_misc_serv_txStatus, les_misc_serve_txs, les_server_blockProcessingTime, les_server_req_estimatedTime, les_server_req_relative, les_server_req_relative_body, les_server_req_relative_code, les_server_req_relative_header, les_server_req_relative_helperTrie, les_server_req_relative_proof, les_server_req_relative_receipt, les_server_req_relative_txStatus, les_server_req_relative_txs, les_server_req_servedTime, p2p_handle_eth_66_0x01-p2p_handle_eth_66_0x0a, rpc_duration_all, rpc_duration_eth_getBlockByNumber, rpc_duration_eth_getRootHash_success, state_snapshot_bloom_index, state_snapshot_dirty_account_hit_depth, state_snapshot_dirty_storage_hit_depth, trie_memcache_gc_time, txpool_dropbetweenreorg, txpool_reheap, txpool_reorgtime

Changes

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)
• Changes only for a subset of nodes

Checklist

• I have added at least 2 reviewer or the whole pos-v1 team
• I have added sufficient documentation in code
• I will be resolving comments - if any - by pushing each fix in a separate commit and linking the commit hash in the comment reply

Testing

• I have added unit tests
• I have added tests to CI
• I have tested this code manually on local environment
• I have tested this code manually on remote devnet using express-cli
• I have tested this code manually on mumbai
• I have created new e2e tests into express-cli

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.41 🎉

Comparison is base (c404b3f) 56.82% compared to head (9c1b905) 57.24%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #881      +/-   ##
===========================================
+ Coverage    56.82%   57.24%   +0.41%     
===========================================
  Files          617      617              
  Lines        73592   105323   +31731     
===========================================
+ Hits         41820    60293   +18473     
- Misses       28228    41396   +13168     
- Partials      3544     3634      +90     

Impacted Files	Coverage Δ
metrics/prometheus/collector.go	100.00% <100.00%> (ø)

... and 614 files with indirect coverage changes

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