Implement export to YAML

- add export commands for git sources and kustomizations
- add export e2e tests

cmd/tk/delete_source_git.go

@@ -3,8 +3,8 @@ package main
 import (
 	"context"
 	"fmt"
-	sourcev1 "github.com/fluxcd/source-controller/api/v1alpha1"
 
+	sourcev1 "github.com/fluxcd/source-controller/api/v1alpha1"
 	"github.com/manifoldco/promptui"
 	"github.com/spf13/cobra"
 	"k8s.io/apimachinery/pkg/types"