Added GitHub stars img shield beside Gitter chat button, and Star History Chart at the bottom of Readme

[ritw237]

…tory Chart at the bottom of Readme

Added GitHub stars img shield beside Gitter chat button, and Star History Chart at the bottom of Readme

Description

Motivation and Context

How Has This Been Tested?

Types of changes

• [ ] Content Update (change which fixes an issue or updates an already existing submission)
• [ ] New Article (change which adds functionality)
• [x] Documentation change

Checklist:

• [ ] My code follows the code style of this project.
• [x] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [x] I have made checks to ensure URLs and other resources are valid