Merge #8371: [Qt] Add out-of-sync modal info layer ...renamed signal, code style overhaul (Jonas Schnelli) ...when the header chain is in-sync (Jonas Schnelli) ...out-of-sync modal info layer (Jonas Schnelli) ...the height of the header chain (Jonas Schnelli) ...signal for headers tip changed (Jonas Schnelli) ...Of-Sync warning icon clickable (Jonas Schnelli) ...readable text out of a timeoffset (Jonas Schnelli)