Make util for url

so far a lot of code has forcefully hardcoded `rmrk` but it will fail for other impl like statemine or bsx.

It would be nice to have a util for url

```ts
function toUrl(prefix: string, route: 'user' | 'nft' | 'col', isDetail = false);
```

Originaly posted in:
- https://github.com/kodadot/nft-gallery/issues/2986

Start by locating the hardcoded `rmrk` URL construction across the packages and comparing the user, NFT, and collection routes. The work is done when a shared TypeScript utility supports the stated prefix, route, and detail parameters and the relevant callers no longer force a single implementation prefix.

Written by the indexing model from the issue text.