OAPI: add operation to delete workers

This will remove a worker by soft-deletion. Any task still assigned to
the worker will be requeued.

Note that this removal should only happen when the worker is offline, or
it will cause errors on the worker as its credentials will not be
accepted any more.

pkg/api/flamenco-openapi.yaml

@@ -461,6 +461,27 @@ paths:
           content:
             application/json:
               schema: { $ref: "#/components/schemas/Worker" }
+    delete:
+      operationId: deleteWorker
+      summary: >
+        Remove the given worker. It is recommended to only call this function
+        when the worker is in `offline` state. If the worker is still running,
+        stop it first. Any task still assigned to the worker will be requeued.
+      tags: [worker-mgt]
+      parameters:
+        - name: worker_id
+          in: path
+          required: true
+          schema: { type: string, format: uuid }
+      responses:
+        "204":
+          description: Normal response, worker has been deleted
+        default:
+          description: Unexpected error.
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
 
   /api/v3/worker-mgt/workers/{worker_id}/setstatus:
     summary: Request a status change for the given worker.
@@ -1936,6 +1957,10 @@ components:
         "status_change":
           $ref: "#/components/schemas/WorkerStatusChangeRequest"
         "version": { type: string }
+        "deleted_at":
+          type: string
+          format: date-time
+          description: This is only set when the worker was deleted.
       required: [id, name, updated, status, version]
 
     SocketIOSubscription: