Remove ports just before usage. Use network specific folders.

[Bushstar]

Summary

• Move removal of old ports.lock to just before it is created again to avoid removing it for an already running instance.
• Use network specific directories so we can use ports auto for mainnet, testnet, changi and regtest on the same data directory.

Implications

• Storage

  • Database reindex required
  • Database reindex optional
  • Database reindex not required
  • None

• Consensus

  • Network upgrade required
  • Includes backward compatible changes
  • Includes consensus workarounds
  • Includes consensus refactors
  • None