CloudMigrations: Refactor API for async work (#89084)

* rename some stuff

* more renaming

* clean up api

* rename more functions

* rename cms -> gms

* update comment

* update swagger gen

* update endpoints

* overzealous

* final touches

* dont modify existing migrations

* break structs into domain and dtos

* add some conversion funcs

* fix build

* update frontend

* try to make swagger happy

pkg/services/cloudmigration/gmsclient/inmemory_client.go

@@ -0,0 +1,45 @@
+package gmsclient
+
+import (
+	"context"
+	"math/rand"
+
+	"github.com/grafana/grafana/pkg/services/cloudmigration"
+)
+
+// NewInMemoryClient returns an implementation of Client that returns canned responses
+func NewInMemoryClient() Client {
+	return &memoryClientImpl{}
+}
+
+type memoryClientImpl struct{}
+
+func (c *memoryClientImpl) ValidateKey(ctx context.Context, cm cloudmigration.CloudMigrationSession) error {
+	return nil
+}
+
+func (c *memoryClientImpl) MigrateData(
+	ctx context.Context,
+	cm cloudmigration.CloudMigrationSession,
+	request cloudmigration.MigrateDataRequest,
+) (*cloudmigration.MigrateDataResponse, error) {
+	result := cloudmigration.MigrateDataResponse{
+		Items: make([]cloudmigration.MigrateDataResponseItem, len(request.Items)),
+	}
+
+	for i, v := range request.Items {
+		result.Items[i] = cloudmigration.MigrateDataResponseItem{
+			Type:   v.Type,
+			RefID:  v.RefID,
+			Status: cloudmigration.ItemStatusOK,
+		}
+	}
+
+	// simulate flakiness on one random item
+	i := rand.Intn(len(result.Items))
+	failedItem := result.Items[i]
+	failedItem.Status, failedItem.Error = cloudmigration.ItemStatusError, "simulated random error"
+	result.Items[i] = failedItem
+
+	return &result, nil
+}