V14/feature/all segment endpoint

[Migaroez]

Prerequisites

• I have added steps to test this contribution in the description below

Description

This PR adds the contractual stable endpoint to retrieve all "defined" (content) segments. Since Umbraco has no way (yet?) to define segments out of the box, we supply a noop implementation of the service behind the endpoint to just return an empty paged list.

Testing

Consider basic Get endpoint testing including authorization with settings section
You can use the following code to quickly override the service to return something.

using Umbraco.Cms.Core;
using Umbraco.Cms.Core.Composing;
using Umbraco.Cms.Core.Models;
using Umbraco.Cms.Core.Services;
using Umbraco.Cms.Core.Services.OperationStatus;

namespace Umbraco.Cms.Web.UI;

public class SegmentService : ISegmentService
{
    private static readonly Segment[] segments = new Segment[] {
        new Segment
        {
            Alias = "segment-one",
            Name = "First Segment"
        },
        new Segment
        {
            Alias = "segment-two",
            Name = "Second Segment"
        },
        new Segment
        {
            Alias = "segment-three",
            Name = "Thrird Segment"
        },
    };

    public async Task<Attempt<PagedModel<Segment>?, SegmentOperationStatus>> GetPagedSegmentsAsync(int skip = 0, int take = 100)
    {
        return await Task.FromResult(Attempt.SucceedWithStatus<PagedModel<Segment>?, SegmentOperationStatus>(
            SegmentOperationStatus.Success,
            new PagedModel<Segment> { Total = segments.Length, Items = segments.Skip(0).Take(take) }));
    }
}

public class SegmentServiceOverrideComposer : IComposer
{
    public void Compose(IUmbracoBuilder builder) => builder.Services.AddUnique<ISegmentService, SegmentService>();
}

[Zeegaan]

Looks good and tests good, found 2 small things 😁