[PM-6511] New i18n for angular (#8122)

* Use state provider to store preferred language

* migrate preferred language

* Use new i18n provider to get LOCAL_ID

* Fix preloaded english i18n

This is a mock service that forces english translations, it doesn't need the i18n interface that allows changing of locales.

* PR improvements

* Fixup merge

libs/common/src/state-migrations/migrations/32-move-preferred-language.ts

@@ -0,0 +1,39 @@
+import { MigrationHelper } from "../migration-helper";
+import { Migrator } from "../migrator";
+
+type ExpectedGlobal = {
+  locale?: string;
+};
+
+export const LOCALE_KEY = {
+  key: "locale",
+  stateDefinition: {
+    name: "translation",
+  },
+};
+
+export class PreferredLanguageMigrator extends Migrator<31, 32> {
+  async migrate(helper: MigrationHelper): Promise<void> {
+    // global state
+    const global = await helper.get<ExpectedGlobal>("global");
+    if (!global?.locale) {
+      return;
+    }
+
+    await helper.setToGlobal(LOCALE_KEY, global.locale);
+    delete global.locale;
+    await helper.set("global", global);
+  }
+
+  async rollback(helper: MigrationHelper): Promise<void> {
+    const locale = await helper.getFromGlobal<string>(LOCALE_KEY);
+
+    if (!locale) {
+      return;
+    }
+    const global = (await helper.get<ExpectedGlobal>("global")) ?? {};
+    global.locale = locale;
+    await helper.set("global", global);
+    await helper.setToGlobal(LOCALE_KEY, null);
+  }
+}