Merge #8637: Compact Block Tweaks (rebase of #8235)

3ac6de0 Align constant names for maximum compact block / blocktxn depth (Pieter Wuille)
b2e93a3 Add cmpctblock to debug help list (instagibbs)
fe998e9 More agressively filter compact block requests (Matt Corallo)
02a337d Dont remove a "preferred" cmpctblock peer if they provide a block (Matt Corallo)