Feature: Allow customization of "Elsewhere" node links

[vidplace7]

In the Node view, there are links to "Elsewhere".

Example:
https://info.mtnme.sh/node_6eb383a5.html

Elsewhere
Armooo's MeshView
Bay Mesh Explorer
Liam's Map
MeshMap

Currently these links are hardcoded in frontend/src/pages/Node.tsx and frontend/src/pages/Map.tsx to values that are unique to the Bay Area.
Please allow these links to be customized in the config.

[kevinelliott]

@vidplace7 You are right! This is definitely something worth doing. In our "next UI" branch we have removed them from the nav bar entirely, and will allow them to be customized on the node detail.

Additionally, we'll be creating a new dedicated page for centralizing general Meshtastic tooling and external links (and this page will be customizable and/or disable-able).