Updated README.md with Screenshots for all the pages

[ManishS6]

Fixes #(issue number)

Fixes #442

Describe the changes you've made

The Screenshots corresponding to the Loading Screen, Login Page, Main Form along with an image of the Banner were updated in README.md under the heading 'A sneak peek into what we have here🙈'

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

NA

Deploy your changes to github page or netlify and mention deployment link:

NA

Checklist

• [x] I have mentioned related issue number in PR description.
• [x] I have added screenshots and related demo links of my changes..
• [x] The title of my pull request is a short description of the requested changes.
• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly.
• [x] Open Source Program name: Hacktoberfest 2021

[QAZIMAAZARSHAD]

@ManishS6 images are not fine.

And these are not all the screenshots.

[ManishS6]

@ManishS6 images are not fine.

And these are not all the screenshots.

@QAZIMAAZARSHAD Could you please tell me whats wrong with these images, so that I could start again.

[QAZIMAAZARSHAD]

[QAZIMAAZARSHAD]

And remove the banner image.

Also, add screenshots of all pages. Sign-up page Forget Password page Feedback page Help page Show one page with dark theme

[ManishS6]

@QAZIMAAZARSHAD on it.