Binding to graph API V1

[hrandika]

Purpose

Binding Microsoft Graph API v1 to work with Azure AD.

Goals

Act Azure AD as the external key manger for WSO2 APIM (3.2.0 and later versions)

Approach

Implement API provided by org.wso2.carbon.apimgt.impl.AbstractKeyManager

Documentation

Reffer README.md

Automation tests

• Unit tests

  None

• Integration tests

  Test are commented out,Update test with details with client_id and client_secret

Security checks

• Followed secure coding standards in http://wso2.com/technical-reports/wso2-secure-engineering-guidelines? no
• Ran FindSecurityBugs plugin and verified report? no
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets? yes

Test environment

JDK 11

Learning

https://docs.microsoft.com/en-us/azure/active-directory/develop/quickstart-create-new-tenant

[CLAassistant]

All committers have signed the CLA.

[tharindu1st]

include spotbugs and checkstyle plugins https://github.com/wso2-extensions/apim-km-wso2is/blob/master/pom.xml#L61-L104 @hrandika

[hrandika]

PR updated with above changes

[hrandika]

updated the PR with request changes