This commit is intended to be as close to a move-only commit as
possible, and lingering ugliness will be resolved in subsequent
commits.

A few variables that are passed in by value instead of by reference
deserve explanation:
- fReset and fReindexChainstate are both local variables in AppInitMain
  and are not modified in the sequence
- fPruneMode, despite being a global, is only modified in
  AppInitParameterInteraction, long before LoadChainstate is called

ninja all check-all