Add "output" flag to the bundle sync command (#1853)

## Changes
We want to use 'bundle sync' in the vscode extension before running a
file as an ad-hoc job (or through the context api). Right now we use
bundle deploy in these cases, but deploying bundle resources is not
always expected when you just want to quickly run a file. Sync makes
more sense in these cases, but we still want to have verbose output to
see what's happening.

In the 'deploy' command we have hidden 'verbose' flag. For the sync I've
just added 'output' flag, handling both json and text cases, similar to
how it's done in the non-bundle `sync` command. The flag is not hidden
(although we still don't show any output by default, if the flag is not
set).

VSCode Extension PR:
databricks/databricks-vscode#1401


## Tests
Manually

cmd/bundle/sync.go

@@ -1,14 +1,17 @@
 package bundle
 
 import (
+	"context"
 	"fmt"
+	"io"
 	"time"
 
 	"github.com/databricks/cli/bundle"
 	"github.com/databricks/cli/bundle/deploy/files"
 	"github.com/databricks/cli/bundle/phases"
 	"github.com/databricks/cli/cmd/bundle/utils"
 	"github.com/databricks/cli/cmd/root"
+	"github.com/databricks/cli/libs/flags"
 	"github.com/databricks/cli/libs/log"
 	"github.com/databricks/cli/libs/sync"
 	"github.com/spf13/cobra"
@@ -18,6 +21,7 @@ type syncFlags struct {
 	interval time.Duration
 	full     bool
 	watch    bool
+	output   flags.Output
 }
 
 func (f *syncFlags) syncOptionsFromBundle(cmd *cobra.Command, b *bundle.Bundle) (*sync.SyncOptions, error) {
@@ -26,6 +30,21 @@ func (f *syncFlags) syncOptionsFromBundle(cmd *cobra.Command, b *bundle.Bundle)
 		return nil, fmt.Errorf("cannot get sync options: %w", err)
 	}
 
+	if f.output != "" {
+		var outputFunc func(context.Context, <-chan sync.Event, io.Writer)
+		switch f.output {
+		case flags.OutputText:
+			outputFunc = sync.TextOutput
+		case flags.OutputJSON:
+			outputFunc = sync.JsonOutput
+		}
+		if outputFunc != nil {
+			opts.OutputHandler = func(ctx context.Context, c <-chan sync.Event) {
+				outputFunc(ctx, c, cmd.OutOrStdout())
+			}
+		}
+	}
+
 	opts.Full = f.full
 	opts.PollInterval = f.interval
 	return opts, nil
@@ -42,6 +61,7 @@ func newSyncCommand() *cobra.Command {
 	cmd.Flags().DurationVar(&f.interval, "interval", 1*time.Second, "file system polling interval (for --watch)")
 	cmd.Flags().BoolVar(&f.full, "full", false, "perform full synchronization (default is incremental)")
 	cmd.Flags().BoolVar(&f.watch, "watch", false, "watch local file system for changes")
+	cmd.Flags().Var(&f.output, "output", "type of the output format")
 
 	cmd.RunE = func(cmd *cobra.Command, args []string) error {
 		ctx := cmd.Context()
@@ -65,6 +85,7 @@ func newSyncCommand() *cobra.Command {
 		if err != nil {
 			return err
 		}
+		defer s.Close()
 
 		log.Infof(ctx, "Remote file sync location: %v", opts.RemotePath)