ci: move public-api goldens to goldens directory (#35768)

Moves the public api .d.ts files from tools/public_api_guard to
goldens/public-api.

Additionally, provides a README in the goldens directory and a script
assist in testing the current state of the repo against the goldens as
well as a command for accepting all changes to the goldens in a single
command.

PR Close #35768

goldens/public-api/platform-server/platform-server.d.ts

@@ -0,0 +1,38 @@
+export declare const BEFORE_APP_SERIALIZED: InjectionToken<(() => void | Promise<void>)[]>;
+
+export declare const INITIAL_CONFIG: InjectionToken<PlatformConfig>;
+
+export declare interface PlatformConfig {
+    document?: string;
+    url?: string;
+}
+
+export declare const platformDynamicServer: (extraProviders?: StaticProvider[] | undefined) => PlatformRef;
+
+export declare const platformServer: (extraProviders?: StaticProvider[] | undefined) => PlatformRef;
+
+export declare class PlatformState {
+    constructor(_doc: any);
+    getDocument(): any;
+    renderToString(): string;
+}
+
+export declare function renderModule<T>(module: Type<T>, options: {
+    document?: string;
+    url?: string;
+    extraProviders?: StaticProvider[];
+}): Promise<string>;
+
+export declare function renderModuleFactory<T>(moduleFactory: NgModuleFactory<T>, options: {
+    document?: string;
+    url?: string;
+    extraProviders?: StaticProvider[];
+}): Promise<string>;
+
+export declare class ServerModule {
+}
+
+export declare class ServerTransferStateModule {
+}
+
+export declare const VERSION: Version;