Creating new redirect service + fixing getMemberWikis() function

This PR introduces a new /go page that serves as a redirect gateway to any member NIWA wiki.

URL format: https://niwanetwork.org/go/{site}/{article}

Example: https://niwanetwork.org/go/nookipedia/Tom_Nook

See screenshot:

The main driver for this is the proposed NIWA article ID property on Wikidata, which requires a central redirection service.

While we could technically use Nintendo Wiki's interwiki links, I'm proposing this system at the top-level site for a few reasons:

Provides a more user-friendly explanation for how the service works
Automatically updates when we add new members
Nintendo Wiki is its own wiki that can manage its interwiki links however it wants (including removing, renaming, etc.); by having a separate redirection service at the org level, we can ensure links stay consistent and meet org-level needs
- To that point, Nintendo Wiki has multiple interwiki links for some wikis -- which can be fine for Nintendo Wiki's purposes, but is a point of concern in the Wikidata discussion.

This PR also fixes the getMemberWiki function when no language is provided.

niwanetwork / niwa-website