whois: Add bitfield performance subcommand

[alexggh]

Add BitfieldPerformace subcommand that uses the onchain data to list the validator's performance regarding the availability bitfields. The tool logic which validators don't have the right performance is really naive, but useful it was used in root causing: paritytech/polkadot-sdk#6910.

The command just crawls back from a give start block a specified number of blocks a prints the stats about validators that are bellow a user-defined performance threshold. For example you can use the tool to determine all validators that didn't populate their bitfields in 30% of the relay chain blocks.

Usage:

polkadot-whois --ws <WS> --session-index <SESSION_INDEX> bit-fields-performance \
  <START_BLOCK>   # The block to start from
  <NUM_TO_SKIP>   # Number of blocks to skip between two queries
  <NUM_BLOCKS>  # Number of blocks to query
  <NUM_SESSIONS_BELLOW_THRESHOLD>  # Print only validators that have poor performance for this number of sessions
  <POOR_PERFORMANCE_THRESHOLD> # Consider validators as having poor performance if they didn't properly populate their bitfields at least this number of times.

Output example

cargo run  --bin polkadot-whois --  --ws=wss://polkadot-rpc-tn.dwellir.com \
--bootnodes /dns/polkadot-boot.dwellir.com/tcp/30334/ws/p2p/12D3KooWKvdDyRKqUfSAaUCbYiLwKY8uK3wDWpCuy2FiDLbkPTDJ   \
--session-index 10114 bit-fields-performance 24167182 20 30 1 30.0


session: 10114 timestamp: 2025-01-06 09:36
block_start: 24167182, session: 10114: validator: 0 has 0 zero bits 0.000%
block_start: 24167182, session: 10114: validator: 1 has 0 zero bits 0.000%
block_start: 24167182, session: 10114: validator: 2 has 0 zero bits 0.000%
block_start: 24167182, session: 10114: validator: 3 has 0 zero bits 0.000%
....
block_start: 24167182, session: 10114: validator: 211 has 30 zero bits 100.000%
block_start: 24167182, session: 10114: validator: 212 has 0 zero bits 0.000%
block_start: 24167182, session: 10114: validator: 213 has 30 zero bits 100.000%
block_start: 24167182, session: 10114: validator: 495 has 19 zero bits 65.517%
block_start: 24167182, session: 10114: validator: 496 has 0 zero bits 0.000%
block_start: 24167182, session: 10114: validator: 497 has 0 zero bits 0.000%
block_start: 24167182, session: 10114: validator: 498 has 0 zero bits 0.000%

block_start: 24167182, session: 10114: 2025-01-06 09:36 Number of validators with 10% missing 89 count_all_with_0 1

block_start: 24167182, account: 5C4mJ9LFLkUJ9ccUrsQtHtU1WpmijdwRzH3PCZXCGLEVZaL8 name: Parity Polkadot/v1.12.0-b4016902ac7 (29107)
     at 2025-01-06 09:36 session: 10114, has 28 with zero bits, 96.55% percent
block_start: 24167182, account: 5C5mTZZkUqHinG4j5N4DmpmqEZPwuLfLjpqjuEzkNRokannM name: Parity Polkadot/v1.16.2-dba2dd59101 (RfnUEAbt)
     at 2025-01-06 09:36 session: 10114, has 12 with zero bits, 40.00% percent
block_start: 24167182, account: 5CB9tg2F96XhpDwJn15ChmrKxdGoHrwGxst6DfbGChdmNboj name: Parity Polkadot/v1.16.2-dba2dd59101 (cojakr7ca2694o4mno30)
     at 2025-01-06 09:36 session: 10114, has 28 with zero bits, 93.33% percent
block_start: 24167182, account: 5CD1tq46tqb255XLZZUHsWmS7pv9NqCLTD6PXpgqGV58b5c2 name: Parity Polkadot/v1.16.1-835e0767fe8 (BitcoinSuisse val23)
     at 2025-01-06 09:36 session: 10114, has 30 with zero bits, 100.00% percent
block_start: 24167182, account: 5HphQUNBfBnaRxFjMdjp5AJJBm8bT59qGq72CxgHhQLYLyXo name: Parity Polkadot/v1.16.2-dba2dd59101 (FIGMENT-1 tor-7)
     at 2025-01-06 09:36 session: 10114, has 30 with zero bits, 100.00% percent

[AndreiEres]

Suggested change

	BitFieldsPerformance(BitFieldsPerformance),
	BitfieldsPerformance(BitfieldsPerformance),

[AndreiEres]

I believe we should use the common spelling for bitfields

[AndreiEres]

shouldn't we print some output on error?