apis for add and remove roles

[debamitra]

What kind of change does this PR introduce

What is the current behavior

What is the new behavior

Checklist for this PR

• [ ] I have read contributing guidelines.
• [ ] I executed npm run lint locally to format my code.
• [ ] I added revelant Tests to verify my code.
• [ ] All tests npm run test ran successfully.
• [ ] Pull request is towards develop branch.
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• [ ] Ready to be merged