Implemented Sharebutton to ask while sharing

[akash-rajak]

fixes #126

Describe the changes you've made

here implemented the share button in such a way that first it will show the user tax info and then ask the permission of sharing via email. if use click on OK , the message will be sent else not sent.

and for sharing process also, there will be dialog box showing information of sharing status, like login successful, message sent or message not sent.

Describe if there is any unusual behaviour of your code(Write NA if there isn't)

NA

Checklist

• [ ] I have added my name in the contributors list at the end of README.md file.
• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have added tests to cover my changes.
• [x] All new and existing tests passed.
• [x] The title of my pull request is a short description of the requested changes.
• [ ] Open Source Program names(OPTIONAL: If you participated in any open-source program then please mention the program name here)

[akash-rajak]

@QAZIMAAZARSHAD , please check this one , have made changes.