Migration to `openrailwaymap.app` domain

[hiddewie]

First part in #430

Hosting the UI and tiles on Fly.io is getting expensive. Instead, let Cloudflare proxy and cache all assets and tiles. This should improve both latency, cache hit rates and data transfer.

There will be some graceful migration period were both openrailwaymap.fly.dev and openrailwaymap.app work, and after that a redirect.

[hiddewie]

I also opened OpenRailwayMap#132 to officially ask to integrate this vector map into the openrailwaymap.org domain.

[hiddewie]

Full redirect in #443

[hiddewie]

API seems broken at the moment, returns 502 responses.

[hiddewie]

Updated references to the domain in #453

Updated JSOM preset source https://josm.openstreetmap.de/wiki/PresetsSource

Updated wiki in:

• https://wiki.openstreetmap.org/wiki/They_are_using_OpenStreetMap
• https://wiki.openstreetmap.org/wiki/OpenHistoricalMap/Bibliography
• OpenRailwayMap page was already updated (https://wiki.openstreetmap.org/w/index.php?title=OpenRailwayMap&diff=2871702&oldid=2847949)

[hiddewie]

API seems broken at the moment, returns 502 responses.

This is a resource problem in the deployment. Unrelated to this issue.