Update content of Service Manual - Backlink

[MagdalenaLarge]

As a Software Developer,
I want to remove the Backlink component from the Service Manual and integrate it as a single breadcrumb variant within the Breadcrumbs component,
so that users can find it more easily.

Description:
As an outcome of ticket #49 , it was identified that all documentation of the Backlink component needs to be removed from the website, as it is now deprecated and replaced by the Breadcrumb component. The Backlink should be incorporated as a single Breadcrumb variant within the Breadcrumb component. Additionally, "Backlink" should be added as a search term for the Breadcrumb component.

Acceptance Criteria:

1. The Backlink component is removed from the Service Manual.
2. All documentation related to the Backlink component is removed and incorporated into the single breadcrumb variant on the website.
3. The Backlink is added as a variant of the Breadcrumbs component.
4. Users can search for "Backlink" using the search field.
5. Users can access the "Backlink" in the Breadcrumbs using the search functionality.

Visualisation/Input from UCD

Linked User stories/epics
See above

Technical details (optional)
MVP (optional)