LegacyMapper/Configuration.php:
- Added 'pdo_sqlite' => 'sqlite3' to the driverMap so SQLite connections
  are accepted instead of throwing 'Could not map database driver to Legacy
  Stack database implementation'. The legacy SQLite3 handler is used.
- After the driver/credential foreach, when driver is pdo_sqlite, injects
  DBAL's 'path' key as site.ini/DatabaseSettings/Database. DBAL stores the
  SQLite file path under 'path' (not 'dbname'), so without this the legacy
  kernel received no Database setting and could not open the .db file.

Fixes: composer create-project aborts during generateAutoloads when the
chosen database driver is pdo_sqlite.