Move 15 loose scripts from contrib/ root to contrib/scripts/
Consolidate all standalone utility scripts into contrib/scripts/:
- Perl: avg_blocktime.pl, block_time.pl, gen-zaddrs.pl, sda_checkpoints.pl,
sdl_checkpoints.pl, hush_block_subsidy_per_halving, hush_halvings,
hush_scanner, hush_supply, hush_supply_old
- Shell: fresh_clone_compile_and_run.sh, tidy_datadir.sh, dragonx_scanner
- Python: convert_address.py
- BAT: hush-uri.bat
Update path references in contrib/README.md, doc/OLD_WALLETS.md,
doc/relnotes/README.md, and sdl_checkpoints.pl.
a2647b106f