Consolidate localization behavior and init to a coreLocalizer function and singleton
Explicitly support `en-US` locale
Rename coreData to coreFileFetcher and export a singleton rather than using a property of coreContext
Add `apiConnections` property of coreContext to simplify adding a source switcher
Replace some init functions with re-callable, promise-supporting `ensureLoaded` functions
Make coreContext itself load the UI if a container has been specified at init time
Fix code tests
This feature requires P31 property to be present
in the data item. For an example, see
https://wiki.openstreetmap.org/wiki/Item:Q104#P31
Once the bot populates them in the data items,
it will automatically work for all existing keys/tags.
* Takes data directly from the Wikibase data items (OSM Wiki)
https://wiki.openstreetmap.org/wiki/OpenStreetMap:Data_Items
* Understands the difference in regions - e.g. will show different
images depending on the local settings
* Perf: Single request will get both the tag and key description