test: add block contents validator

[MiroslavGatsanoga]

Description:

Create additional block stream validator that will validate the structure of the contents in each block.

Related issue(s):

Fixes https://github.com/hashgraph/hedera-services/issues/15474

Notes for reviewer:

Used this doc for defining the checks that the validator makes. There were some exceptions to the rules described, more specifically:

• For the first block produced by a HapiTest suite run the block_header is followed by state_changes (instead of event_header), due to state migration.
• There are a lot of blocks that don't have user transaction in them which always contain items of the following types: block_header, event_header, state_changes and state_proof. Those blocks do not adhere to the general rule of An event_header SHALL be followed by one or more event_transaction items.
• There are two TODOs left to be discussed, namely:
  • In general, a block_header SHALL be followed by an event_header, but for hapiTestRestart we get state change singleton update for BLOCK_INFO_VALUE for a block different than the first one
  • The rule for An event_header SHALL be followed by one or more event_transaction items looks like not quite true since we can have multiple event headers in a row e.g. check results from running hapiTestToken.

Checklist

• [X] Documented (Code comments, README, etc.)
• [X] Tested (unit, integration, etc.)