Backend: Add `readmeHtml` GQL field to CiCatalogResource

Add a readmeHtml field to ciCatalogResourceType that returns the content of the README file converted from markdown to HTML

Context:

We need to add the capability in graphql to take a raw blob, which will be markdown and return a HTML formatted version using MarkupHelper.

In our case, if we had like readmeHtmlon ciCatalogResourceType, we would want that field to load the content of the README of a Component repository and convert it from markdown to HTML, then return the HTML as the field value so that the client can use this to render the markup.

Implementation

Description	MR
Add GraphQL field readme_html to CiCatalogResource	!122261 (merged)