[Impl] Prepare output to visualize LMD Ghost

[yudetamago]

What to visualize

• message chain
  • parent child arrow
  • justification arrow
  • block with score
• validator weight

Different coloring

• last finalized block
• blocks in choiced chain
• estimated block
• blocks in latest messages

[yudetamago]

An example visualization has been done in #31 but visualising itself is out of scope of this project.