feat: add core workspace module (#145)

The core workspace module(WorkspaceService) is a foundational component
that enables the implementation of workspace features within OSD
plugins. The purpose of the core workspace module is to provide
a framework for workspace implementations.

This module does not implement specific workspace
functionality but provides the essential infrastructure for plugins to
extend and customize workspace features, it maintains a shared
workspace state(observables) across the entire application to ensure
a consistent and up-to-date view of workspace-related information to
all parts of the application.

---------

Signed-off-by: Yulong Ruan <[email protected]>

src/core/public/index.ts

@@ -351,4 +351,4 @@ export {
 
 export { __osdBootstrap__ } from './osd_bootstrap';
 
-export { WorkspacesStart, WorkspacesSetup } from './workspace';
+export { WorkspacesStart, WorkspacesSetup, WorkspacesService } from './workspace';

src/core/types/workspace.ts

@@ -12,4 +12,5 @@ export interface WorkspaceAttribute {
   icon?: string;
   reserved?: boolean;
   defaultVISTheme?: string;
+  reserved?: boolean;
 }