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
  • [x] None

• Consensus

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