bunch of stuff, good luck. still need to fix user-by-mode thing

lib/keys.dart.example

@@ -0,0 +1,3 @@
+// Example OSM OAuth key config
+const String kOsmProdClientId = 'YOUR_PROD_CLIENT_ID_HERE';
+const String kOsmSandboxClientId = 'YOUR_SANDBOX_CLIENT_ID_HERE';