[Wallet] Send transaction

[tomaszantas]

Add send transaction command

[alex1307]

At the moment the tauri command transfer accept the following json struct:

{ 
       "paymenents": [ {
              "amount": u64,
              "fee_per_gram": u64 [value could be between 1 and 5]
              "message": String,
              "address": String,
              "payment_type": [0, 1].  STANDARD_MIMBLEWIMBLE = 0; ONE_SIDED = 1;
       }]
}

and returns

{ 
       "paymenents": [{
              "transaction_id": u64,
              "error_message": String,
              "address": String,
              "is_successful": true|false
       }]
}

The response is sent to tari://wallet_transaction as well. Let me know whether the contract is OK or I should make some changes.