[serverless][local stack] Refactor ssl changes

[bhapas]

As per #1669 (comment) and #1669 (comment) , check if the refactor is possible

• Generate certificates earlier so we don't need to update policy Enable ssl between logstash and agent #1669 (comment)
• Review need of PKCS8 conversion Enable ssl between logstash and agent #1669 (comment)
  • Fixed in Pre-build logstash image with plugin and configuration #1687