Added GitHub Oauth Login and Registration

[codesankalp]

Description

Added the code to make POST request on backend to send code and recieve access_token.

Fixes #106

Type of Change:

• Code
• User Interface
• Documentation
• Tests

Code/Quality Assurance Only

• This change requires a documentation update (software upgrade on readme file)
• New feature (non-breaking change which adds functionality pre-approved by mentors)

How Has This Been Tested?

Checklist:

• [x] My PR follows the style guidelines of this project
• [x] I have performed a self-review of my own code or materials
• [x] I have commented on my code or provided relevant documentation, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] I have added tests for my change.

Code/Quality Assurance Only

• [x] My changes generate no new warnings

[codesankalp]

Backend Pull request to test this feature: https://github.com/anitab-org/open-source-programs-backend/pull/109

If facing a problem in running the development server of the frontend. Try this:

rm -rf node_modules/
npm install --force
npm start

[codesankalp]

@isabelcosta Can you review this PR?

[isabelcosta]

@codesankalp I just merged the prettier styling PR 🙈 could you please fix the merge conflicts?

[codesankalp]

@isabelcosta Removed the merge conflict but there is a problem with QA-Checks.

[codesankalp]

@isabelcosta Should I add the workflow for tests here?

[codesankalp]

I am fixing the conflicts and Will update the PR.