[easy][refactor] Move env var to owner package (#2282)

## Summary

TSIA

## How was it tested?

Author: mikeland73

internal/boxcli/featureflag/feature.go

@@ -10,9 +10,10 @@ import (
 	"testing"
 
 	"go.jetpack.io/devbox/internal/build"
-	"go.jetpack.io/devbox/internal/envir"
 )
 
+const envNamePrefix = "DEVBOX_FEATURE_"
+
 type feature struct {
 	name    string
 	enabled bool
@@ -48,7 +49,7 @@ func (f *feature) Enabled() bool {
 	if f == nil {
 		return false
 	}
-	if on, err := strconv.ParseBool(os.Getenv(envir.DevboxFeaturePrefix + f.name)); err == nil {
+	if on, err := strconv.ParseBool(os.Getenv(envNamePrefix + f.name)); err == nil {
 		status := "enabled"
 		if !on {
 			status = "disabled"
@@ -70,7 +71,7 @@ func (f *feature) EnableOnDev() *feature {
 }
 
 func (f *feature) EnableForTest(t *testing.T) {
-	t.Setenv(envir.DevboxFeaturePrefix+f.name, "1")
+	t.Setenv(envNamePrefix+f.name, "1")
 }
 
 // All returns a map of all known features flags and whether they're enabled.

internal/boxcli/featureflag/feature_test.go

@@ -5,8 +5,6 @@ package featureflag
 
 import (
 	"testing"
-
-	"go.jetpack.io/devbox/internal/envir"
 )
 
 func TestEnabledFeature(t *testing.T) {
@@ -28,7 +26,7 @@ func TestDisabledFeature(t *testing.T) {
 func TestEnabledFeatureEnv(t *testing.T) {
 	name := "TestEnabledFeatureEnv"
 	disable(name)
-	t.Setenv(envir.DevboxFeaturePrefix+name, "1")
+	t.Setenv(envNamePrefix+name, "1")
 	if !features[name].Enabled() {
 		t.Errorf("got %s.Enabled() = false, want true.", name)
 	}

internal/envir/env.go

@@ -4,9 +4,8 @@
 package envir
 
 const (
-	DevboxCache         = "DEVBOX_CACHE"
-	DevboxFeaturePrefix = "DEVBOX_FEATURE_"
-	DevboxGateway       = "DEVBOX_GATEWAY"
+	DevboxCache   = "DEVBOX_CACHE"
+	DevboxGateway = "DEVBOX_GATEWAY"
 	// DevboxLatestVersion is the latest version available of the devbox CLI binary.
 	// NOTE: it should NOT start with v (like 0.4.8)
 	DevboxLatestVersion  = "DEVBOX_LATEST_VERSION"