add elbscheme to elastic beanstalk

[peterdudfield]

Pull Request

Description

• add elbscheme to eb_app. This should mean we can create internal load balance

How Has This Been Tested?

• made a temperaory one on AWS ELB, and the load balancer worked as expected

Checklist:

• My code follows OCF's coding style guidelines
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I have checked my code and corrected any misspellings