Deprecate services in favor of serializers

[Tansito]

What is the expected enhancement?

In #1147 I started a refactorization moving bussiness logic from views to services. Investing some more time learning about DRF I think Serializers can do the work that Services are doing right now simplifying the current logic. I will create a little PR testing this approach to see how it fits with Programs entity for example.

• Upload end-point refactorization
  • Upload refactorization #1243
• RunExisting end-point refactorization:
  • Fix ExistingProgram serializer #1245
  • Refactorization for run_existing end-point #1267
• Run end-point refactorization
  • Run refactorization #1286