User Management APIs

Being developer first, we have made significant updates and enhancements to the User APIs for easier user management in SuprSend. Also, subscriber is renamed to users in all APIs to avoid confusion with object subscription. Here's a list of all the changes:

• Introduced new APIs to fetch user profile, list users and delete user.
• User update API endpoint has been changed from /event to /user/{{distinct_id}}.
• There are 2 separate APIs to create(upsert) and edit user profile. Any addition or changes in existing user properties can be done using user upsert API. For deletion of property or channel, user edit API can be used. This is done to keep user upsert API structure flat and simple, consistent to how you identify user in workflow trigger.
• Subscriber is renamed to user in all APIs, including user preference APIs.