Add blob example

[nguyer]

It would be great to have an example of sending/receiving a blob. A simple web app that lets users upload an image or view an image that has been shared by other members would be great. Additionally, it would be nice to show how to do this publicly or privately.

[lanasta]

This is the API you need: https://hyperledger.github.io/firefly/swagger/swagger.html#/default/postData

[kajalv]

Hi! Could I take this one?

[priyakhandelwal18]

I'm happy to work on this one!