chore: add experiment toggle for terraform workspace caching (#20559)

Experiments passed to provisioners to determine behavior. This adds
`--experiments` flag to provisioner daemons. Prior to this, provisioners
had no method to turn on/off experiments.

provisionersdk/serve.go

@@ -15,6 +15,7 @@ import (
 	"storj.io/drpc/drpcserver"
 
 	"cdr.dev/slog"
+	"github.com/coder/coder/v2/codersdk"
 	"github.com/coder/coder/v2/codersdk/drpcsdk"
 
 	"github.com/coder/coder/v2/coderd/tracing"
@@ -30,6 +31,7 @@ type ServeOptions struct {
 	Logger              slog.Logger
 	WorkDirectory       string
 	ExternalProvisioner bool
+	Experiments         codersdk.Experiments
 }
 
 type Server interface {