server sided external api calls (#697)

* server sided external api calls

* fix uploading gpx files

* rename api/v1/nominatim with api/v1/geocoding to prepare photon support

* remove NOMINATIM_MAX_RETRIES (side-kick from other PR)

* re-add nominatim url fallback

* docu, env var defaults and fallbacks, docker compose files

* refactor

* furhter refactorings and fixes

* PUBLIC_VALHALLA_ENABLED in docker compose files added

* fix env var names

---------

Co-authored-by: Flomp <Flomp@users.noreply.github.com>

web/src/lib/server/valhalla.ts

@@ -0,0 +1,5 @@
+import { resolveBaseUrl } from "$lib/server/url";
+
+export function getValhallaBaseUrl(): string {
+    return resolveBaseUrl("VALHALLA_URL");
+}