Convert pages to map

[markdumay]

Is your feature request related to a problem? Please describe.
The section-list partial renders a collection of pages as either group of cards, nav, or list. Currently, the page collection is passed as argument to the referenced partials. This limits the option to pass data, such as frontmatter parameters, directly.

Describe the solution you'd like
Pass a map of key-value pairs to assets/card-group.html, assets/nav.html, and assets/list.html instead of a page collection. Move the pagination to the section-list partial to reduce the complexity. Finally, support a new kind to handle data input.

Describe alternatives you've considered
N/A

Additional context
Many Content Management Systems allow direct editing of frontmatter variables. Supporting this data entry improves the editing experience.