Fcu peer refresher

[asdacap]

• Update peer refreshing to use FCU's hashes.

Changes:

• Update peer refreshing to use FCU's hashes. It will now only disconnect if the finalized block is not available from the peer.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Other (please describe):

Testing

• Yes
• No

In case you checked yes, did you write tests??

• Yes
• No

Comments about testing , should you have some (optional)

• Ropsten can sync to head.

[MarekM25]

After review from Łukasz I suggest running nodes with tracing for refreshing in order to observe how the node is behaving. Generally PR is looking good I proposed a few changes

[LukaszRozmej]

Still few thing unaddressed.