feat(wifi_passpoint): plugin added

[daadu]

🚧 Work In Progress 🚧

Related to #290

Options for testing/playing around

• Run example app
• Integrate with your project with following:

  wifi_passpoint:
      git:
          url: https://github.com/daadu/WiFiFlutter
          ref: wifi_passpoint
          path: packages/wifi_passpoint