Add comments about syncing with local.cfg

This seems to be a common question of users. Clarifying via comments.

src/environments/environment.common.ts

@@ -6,6 +6,7 @@ import { RestRequestMethod } from '../app/core/data/rest-request-method';
 export const environment: GlobalConfig = {
   production: true,
   // Angular Universal server settings.
+  // NOTE: these must be "synced" with the 'dspace.ui.url' setting in your backend's local.cfg.
   ui: {
     ssl: false,
     host: 'localhost',
@@ -14,6 +15,8 @@ export const environment: GlobalConfig = {
     nameSpace: '/',
   },
   // The REST API server settings.
+  // NOTE: these must be "synced" with the 'dspace.server.url' setting in your backend's local.cfg.
+  // The 'nameSpace' must always end in "/api" as that's the subpath of the REST API in the backend.
   rest: {
     ssl: true,
     host: 'dspace7.4science.cloud',