Minor changes in Readme.md

[rahulsain]

Related Issuse or bug

• Info about Issue or bug

Fixes: #46

Describe the changes you've made

Optimize the tags and change href in scanit logo to google play store rename file and moved all .png to screenshot folder and updated guidelines.md file href

Type of change

• [x] This change requires a documentation update.

Checklist:

• [x] My code follows the style guidelines of this project.
• [x] I have performed a self-review of my own code.
• [x] I have made corresponding changes to the documentation.
• [x] My changes generate no new warnings.

[rahulsain]

@mishraaditya595 Please go through these changes I have made, it doesn't change any existing functionality.

[mishraaditya595]

Hey @rahulsain, I have already merged your readme PR #50. I liked that better. Good work.