move workspace context interface to workspace lib

src/Umbraco.Web.UI.Client/libs/workspace/context/workspace-context.interface.ts

@@ -0,0 +1,16 @@
+import { Observable } from 'rxjs';
+import { UmbControllerHostInterface } from '@umbraco-cms/backoffice/controller';
+
+export interface UmbWorkspaceContextInterface<T = unknown> {
+	host: UmbControllerHostInterface;
+	repository: any; // TODO: add type
+	isNew: Observable<boolean>;
+	getIsNew(): boolean;
+	setIsNew(value: boolean): void;
+	// TODO: should we consider another name than entity type. File system files are not entities but still have this type.
+	getEntityType(): string;
+	getData(): T;
+	destroy(): void;
+	// TODO: temp solution to bubble validation errors to the UI
+	setValidationErrors?(errorMap: any): void;
+}