refactor: simplify setup of asset paths

apps/server/src/externals.ts

@@ -0,0 +1,12 @@
+/**
+ * This file contains a list of constants that may need to be resolved at runtime
+ */
+
+// =================================================
+// resolve running environment
+const env = process.env.NODE_ENV || 'production';
+
+export const isTest = Boolean(process.env.IS_TEST);
+export const environment = isTest ? 'test' : env;
+export const isDocker = env === 'docker';
+export const isProduction = isDocker || (env === 'production' && !isTest);