[Plugins] Do not overwrite existing user-config files of plugins (#1917)

## Summary

Fixes #1909

Makes two changes:
1. The users control `devbox.d` directory files once the plugin has
generated it for them. Devbox should never be overwriting them. Added
code to check for this.
2. For the code that checks if filepath contains `.devbox` or
`devbox.d`, I now try to make that stricter by checking if filepath
contains `/.devbox/` or `/devbox.d/`. As pointed out in the issue, the
jetpack-mongodb plugin is generating user-configs at
`devbox.d/jetpack-io.devbox-plugins.mongodb` which also contains
`.devbox` string. This will pass checks for `strings.Contains(filepath,
".devbox")` even though that is not the intention of that particular
check.

cc @mikeland73 

## How was it tested?

Repro'd the scenario of the issue.
Added the files via `git init && git commit -a`
Ran `rm -rf .devbox` and `devbox install`
Ran `git status` and confirmed that no `devbox.d` files were modified

Author: savil

internal/devbox/packages.go

@@ -257,7 +257,7 @@ func (d *Devbox) ensureStateIsUpToDate(ctx context.Context, mode installMode) er
 		if upToDate {
 			return nil
 		}
-		ux.Finfo(d.stderr, "Ensuring packages are installed.")
+		ux.Finfo(d.stderr, "Ensuring packages are installed.\n")
 	}
 
 	if mode == install || mode == update || mode == ensure {

internal/plugin/plugin.go

@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"cmp"
 	"encoding/json"
+	"fmt"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -16,6 +17,7 @@ import (
 	"github.com/pkg/errors"
 	"go.jetpack.io/devbox/internal/devconfig/configfile"
 	"go.jetpack.io/devbox/internal/devpkg"
+	"go.jetpack.io/devbox/internal/fileutil"
 
 	"go.jetpack.io/devbox/internal/debug"
 	"go.jetpack.io/devbox/internal/lock"
@@ -24,6 +26,7 @@ import (
 )
 
 const (
+	// TODO rename to devboxPluginUserConfigDirName
 	devboxDirName       = "devbox.d"
 	devboxHiddenDirName = ".devbox"
 	pluginConfigName    = "plugin.json"
@@ -215,14 +218,21 @@ func (m *Manager) shouldCreateFile(
 	pkg *lock.Package,
 	filePath string,
 ) bool {
-	// Only create files in devboxDir if they are not in the lockfile
+	// Only create files in devbox.d directory if they are not in the lockfile
 	pluginInstalled := pkg != nil && pkg.PluginVersion != ""
-	if strings.Contains(filePath, devboxDirName) && pluginInstalled {
+	if strings.Contains(filePath, "/"+devboxDirName+"/") && pluginInstalled {
+		return false
+	}
+
+	// We do not overwrite an existing file in devbox.d. That is user-config that is user-controlled
+	// after the initial file creation via the Devbox plugin.
+	if strings.Contains(filePath, "/"+devboxDirName+"/") && fileutil.Exists(filePath) {
+		fmt.Printf("false for shouldCreateFile b/c it exists: %s\n", filePath)
 		return false
 	}
 
 	// Hidden .devbox files are always replaceable, so ok to recreate
-	if strings.Contains(filePath, devboxHiddenDirName) {
+	if strings.Contains(filePath, "/"+devboxHiddenDirName+"/") {
 		return true
 	}
 	_, err := os.Stat(filePath)