Modification to Slak Nebula Android client

Hi,

We need multiple gateways with a weight capability for unsafe routes added to Nebula Android client. The regular client already supports it but the mobile client does not.

Basically what is needed is this capability:

  # Multiple gateways with a weight, this will balance traffic accordingly
  - route: 192.168.87.0/24
    via:
      - gateway: 10.0.0.1
        weight: 10
      - gateway: 10.0.0.2
        weight: 5

to work on the Android client.

Knowledge of Go, Flutter, Dart, Kotlin is needed. Unsafe routes with multiple gateways must be able to be added and edited both from the UI and from the imported yaml file.