Use Dynamic Routes

[ScriptRaccoon]

This is a continuation of #193, which unified the Svelte components and pages for categories and functors. The routes, and therefore the folder structure in /routes, were still duplicated. This became apparent after adding morphisms in #265. This PR addresses the issue by using dynamic routes instead, which are sufficiently flexible in SvelteKit.

Example

For example, instead of three folders with almost identical logic:

/category-properties  
/functor-properties  
/morphisms-properties  

there is now a single folder that handles all three cases:

/[type]-properties  

The same approach applies to other type-specific routes. This change will become even more beneficial in the future when additional structure types (such as monoidal categories) are added.

Breaking change

The route listing all categories has changed from /categories to /category-list. Similar changes apply to functors and morphisms. In general, all routes associated with a specific type now start with /[type], and plural forms are no longer used.