Scripts for starting screen

[chinmayapancholi13]

This PR adds 2 scripts :

1. To add a "Get Started" button, which the user could tap to start the conversation.
2. To add greeting text at the starting screen. The message for the greeting text could be modified as per one's requirement.

[chinmayapancholi13]

@vedantrathore Could you please take a look at this PR and let me know your views about the utility of these 2 files?

[vedantrathore]

@chinmayapancholi13 these are just bash scripts to do the task, what we need is that it should be integrated with the python flask application so that when the user clicks get started, we can send a response to the server

[chinmayapancholi13]

Agreed. We would have to handle postbacks in the main code as well. Something along the lines of :

                    if messaging_event.get("postback"): 
                        sender_id = messaging_event["sender"]["id"]
                        payload_value =  messaging_event["postback"]["payload"]
                        greeting = "Hi there! :) My name is Monica."
                        send_message_text(sender_id, greeting)

Should I go ahead and add this in the same PR?