Add SKIP_POW_DIFFICULTY_VALIDATION flag to AbstractNet for chains using custom difficulty algorithms like LWMA. Update blockchain.py to skip pow validation when flag is set, relying on server validation and checkpoints instead. Also update Palladium checkpoints.
Add initial configuration files for Palladium chain including servers, checkpoints, and fallback nodes.
Update constants to use Palladium as default network and rename PalladiumMainnet to Palladium for consistency.
