Migrate TokenManager types

Signed-off-by: Johan Haals <johan.haals@gmail.com>

packages/backend-plugin-api/src/services/definitions/TokenManagerService.ts

@@ -14,7 +14,26 @@
  * limitations under the License.
  */
 
-import { TokenManager } from '@backstage/backend-common';
+/**
+ * Interface for creating and validating tokens.
+ *
+ * @public
+ */
+export interface TokenManagerService {
+  /**
+   * Fetches a valid token.
+   *
+   * @remarks
+   *
+   * Tokens are valid for roughly one hour; the actual deadline is set in the
+   * payload `exp` claim. Never hold on to tokens for reuse; always ask for a
+   * new one for each outgoing request. This ensures that you always get a
+   * valid, fresh one.
+   */
+  getToken(): Promise<{ token: string }>;
 
-/** @public */
-export interface TokenManagerService extends TokenManager {}
+  /**
+   * Validates a given token.
+   */
+  authenticate(token: string): Promise<void>;
+}