EDS API: Application Endpoints functionality to be a new API

[javierlozallu]

Problem description
This Operation allows to: Register and manage the routable Application Endpoints of your deployed applications.
Currently the approach is that endpoints are fully managed by the Edge Platform and Developers can ask for this information through GET /apps/{appId}/instances EAM API method.
I don't found any intent related to this capability but I think is very interesting to have it because of two reasons:

• If the developer deploys the application on a hyperscaler
  

• If the developer wants to use their own domains, this relates to a comment in 
  

Shouldn't the AccessEndpoints also contain the protocol #271 to have a new API: Bring Your Own DNS/Endpoint/Whatever which allows the developer to use and manage third party domains (other than the Edge platform). So this contribution will serve as a basis for this.
A different approach I see here is to add it in the onboarding process within the EAM API, but I don't quite like it.

Expected behavior
Create separate yaml for Application end point registry. This is more edge cloud specific but still reusable across the sub projects.

[maheshc01]

PR created for this with initial set of API capabilities. More updates regarding API documentation and standardizing of error codes to be updated as part of the same PR.