Upgrades the wag database to handle a new 'endpoint' field to resolve #12
Bug Fixes:
- After hot upgrade the wireguard endpoint watcher no longer automatically de-authenticate all users as wireguard device creation sets device endpoints to their previous value
Changes:
- make upgrade message a bit clearer to differentiate when a binary needs to be manually copied or is automatically copied
- Wag now stores the last user device endpoint in the SQLite3 database
- wag can now automatically upgrade its own database