refactor: hide git repo path details from more packages (#38601)

Remove `RepoPath` from "models/repo" package, remove `UserPath` from
"models/user" package, use `WithRepo` for more places, fine tune tests.

modules/git/gitrepo/gitrepo.go

@@ -4,7 +4,10 @@
 package gitrepo
 
 import (
+	"io/fs"
+	"os"
 	"path/filepath"
+	"strings"
 	"sync/atomic"
 
 	"gitea.dev/modules/setting"
@@ -39,6 +42,13 @@ func RepoLocalPath(repo RepositoryFacade) string {
 	return setting.RepoRootPath + string(filepath.Separator) + filepath.FromSlash(repoLoc)
 }
 
+func UserLocalPath(userName string) string {
+	if setting.RepoRootPath == "" {
+		panic("repo root path is not initialized")
+	}
+	return filepath.Join(setting.RepoRootPath, filepath.Clean(strings.ToLower(userName)))
+}
+
 func repoLogNameByLocation(loc string) string {
 	t := filepath.FromSlash(loc)
 	// hide the parent paths, then the name should be safe for end users
@@ -100,3 +110,7 @@ func (r *repositoryManaged) GitRepoLocation() string {
 func RepositoryManaged(id, loc string) RepositoryFacade {
 	return &repositoryManaged{id: id, loc: filepath.Clean(loc)}
 }
+
+func RepoLocalFS(repo RepositoryFacade) fs.FS {
+	return os.DirFS(RepoLocalPath(repo))
+}