📙 Improving Parse Server AWS guide

[MrMartinR]

Link to section:
https://docs.parseplatform.org/parse-server/guide/#deploying-on-aws-ec2-ubuntu-using-postgresql

What is the issue?
The guide states to install 2 times parse-server, implementing how to add pm2, also improving style.
Can you propose a solution?
a PR is ready with the changes