Content repeated twice - New App Setup - CI

[xavxyz]

The checklist document about CI is repeating twice the ~same content to setup Semaphore: https://okgrow.github.io/guides/docs/new-app-setup-continuous-integration.html

I believe we should "merge" the repeated content in one, keeping the respective best parts of the two.

The links to the CI/deploy scripts are also invalid now. These scripts currently live here (and could live elsewhere in the repo?): https://github.com/okgrow/guides/tree/master/docs/processes-new-app-setup