First draft of NetworkEndpointGroup

[raffaelespazzoli]

Signed-off-by: raffaelespazzoli raffaele.spazzoli@gmail.com

Description of your changes

This is a WIP

Adds NetworkEndpointGroup API

I have:

• [x ] Read and followed Crossplane's contribution process.
• Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

some unit tests have been created

[raffaelespazzoli]

I create this PR to have a place where to discuss an issue I'm having (I will likely have more since this is my first contribution).
I'm getting a golint failure due to high cyclomatic complexity. The code looks good to me and I don't know how to simplify it, so I'm looking for some advice on how to pass this issue. The high cyclomatic score seems to be triggered by a nested if, which is the right thing to do n that context as a switch cannot be used. The Update function in networkendpointgroup.go is where the issue occurs.