docs: Add script and docs to configure postman post deployment

[Ratnesh2003]

Things that I have done:

• Removed the complete steps to run the deployment from the README on the root directory, created a section called SETTING THINGS UP that directs user to go into the /docs folder.
• I have moved in the previous root directory README file to /docs folder.
• Added a POSTMAN_SETUP.md file that provided step-by-step solution on how to configure Postman in order to run the APIs after deployment.
• Added a script postman_setup.sh inside the /scripts directory that automatically creates entry in the /etc/hosts file and uploads all of the required BPMN diagrams to the zeebe ops service.