Create filter options for files

[trueberryless]

Using Lunaria in bigger projects creates long lists and tables, eg Astro Docs Tracker.

Maybe it would be cool to integrate some filtering logic for the files, so you can focus on specific files or groups (or directories).

When thinking about this, two ideas come to my mind (not sure if they both work or match the philosophy of Lunaria):

1. Because Lunaria builds rather static sites, the filters should be specified at build time. This means that the developers can chose, which filters all users can apply to work more efficiently and Lunaria builds the main site and probably some routes for the different filters.
2. For flexibility the user can specify exactly which files to show at runtime.
3. Automatically dynamic filtering based on directories: The filter options cannot be configured by the developer, they automatically apply based on the different directories (eg.: root files, /guides, /concepts, basics). This option also creates static files at build time.

These are just some wild ideas that came to my mind randomly (whilst creating this) :)

• I'm willing to create a PR for the implementation.