param: transactions announced only

[jj1980a]

Description

Introducing txannouncementonly option.
When enabled, the node will gossip transactions to its peers via announcements only.
Default value is false (standard behavior).

This is a convenience option for validators who enable the Fastlane MEV protocol.

Validators participating in the Fastlane protocol have been patching their sentry nodes to achieve the same for more than 2 years. Allowing it as a standard parameter would greatly improve validators experience on each new Bor release.

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
• Created a task in Jira and informed the team for implementation in Erigon client (if applicable)
• Includes RPC methods changes, and the Notion documentation has been updated

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/amoy
• I have created new e2e tests into express-cli