Feature: Custom payment app selection

[jaiminbhut]

I have add a new feature the helps developers to select specific app for payment.

For example, if I only need my users payment through GPay I pass one extra param tez in initializePayment method.

RNUpiPayment.initializePayment({
  vpa: 'john@upi', // or can be john@ybl or mobileNo@upi
  payeeName: 'John Doe',
  amount: '1',
  transactionRef: 'aasf-332-aoei-fn'
}, successCallback, failureCallback,'tez');

So whenever initializePayment method will call only GPay application will open. if app not found then it's returns system message for me it's return No apps can perform this action.