feature(http): improvements on http module. closes (#179)

[emoralesb05]

Description

There is a need to be able to override the service transform in the RESTService at a method level. So now you can pass a specific transform callback that overrides the service level transform function.
#179

What's included?

• REST Methods now accept an extra optional parameter for method level IRestTransform callback to allow more flexibility on response transformations
• Added new onRequestError hook to the IHttpInterceptor interface and usage in HttpInterceptorService (upstreamed from AC)
• Added code-health unit test to RESTService
• Updated docs and README.md

Test Steps

There is no real way to test it without actually using it, so the unit-tests should check if the RESTService acts like it should on every scenario.

• ng serve
• See updated docs in http module
• ng serve to see test the RESTService with its http-rest.service.spec.ts