Showcase SDK rich text resolution

[Simply007]

Motivation

There is nos howcase of the rich text resolution in this sample app.

Proposed solution

Use features directly in the SDK to resolve the richtext:

• https://github.com/kontent-ai/delivery-sdk-php/blob/master/wiki/Resolving-links-to-content-items.md
• https://github.com/kontent-ai/delivery-sdk-php/blob/master/wiki/Resolving-content-items-and-components-in-Rich-text.md

An ideal place it for Article body copy detail.

Additional context

Current state for linked items:

http://127.0.0.1:8000/en-us/articles/show/coffee_beverages_explained