Allow changing the behavior for imported blocks (#5236)

* Added option to disable default block announce

* Added on_block_imported on NetworkService

* Revert "Added on_block_imported on NetworkService"

This reverts commit ba360cad.

* Do not announce block if set to not announce block

* Revert fix

* Moving default announce block to NetworkConfig

* WIP

Forked at: 41bb2193
Parent branch: origin/master

* WIP

Forked at: 41bb2193
Parent branch: origin/master

* Removing boolean in favor of explicit call

* Fixing tests

* WIP

Forked at: 41bb2193
Parent branch: origin/master

* WIP

Forked at: 41bb2193
Parent branch: origin/master

* increase spec_version

* increase spec_version

* Fixed test

* Fixing test

* Renamed should_announce_imported_blocks to announce_imported_blocks

* Updated assert_cmd