Stubs for entity_type endpoints
Adding client calls to the entity types endpoints
 - add entity type is untested b/c there is no delete API (documented anyways) for deleting a type I create
Moving `EntityEndpointFunctionalTest` and its dependencies into proper package
refactored logic for converting Json into its own class with support for paths
Refactoring `EntityTypeEndpoints`
Merge pull request #8 from CruGlobal/feat/7

Entity Type endpoints