RakenEmailService

• use async process for enrichment and send

API endpoints:

1. post for create email and send curl --location --request POST 'http://localhost:8080/api/v1/email/?enrich=true'
   --header 'Content-Type: application/json'
   --data-raw '{ "from":"aa@gmail.com", "to": "bb@gmail.com", "subject": "test", "body": "test" }'

2. get email with status curl --location --request GET 'http://localhost:8080/api/v1/email/1'

more improvements on next sprint

1. add spring security for Authentication and Authorization
2. add api access limit
3. add more unit test for coverage
4. add cc/bcc support