Update user-role grants and revoke handler

[TanmoySG]

requestBody does not have well-defined semantics for GET, HEAD and DELETE operations

DELETE requests do not support a request body.

For op DELETE {{URL}}/api/users/revoke to revoke a role from a user, is not ideal to have a request body.

TODO

• Update the request handler for DELETE op and other user-role ops (grant and revoke) to make it standardized.
• Maybe POST {{URL}}/api/users/{userId}/grant with a Request body containing the role to grant, and entities
• Maybe PATCH {{URL}}/api/users/{userId}/revoke with a Request body containing the role to revoke, and entities
• Maybe PATCH {{URL}}/api/users/{userId}/update with a Request body containing the role to patch, and entities