Refactor Git Attribute & performance optimization (#34154)

This PR moved git attributes related code to `modules/git/attribute` sub
package and moved language stats related code to
`modules/git/languagestats` sub package to make it easier to maintain.

And it also introduced a performance improvement which use the `git
check-attr --source` which can be run in a bare git repository so that
we don't need to create a git index file. The new parameter need a git
version >= 2.40 . If git version less than 2.40, it will fall back to
previous implementation.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: yp05327 <576951401@qq.com>

routers/web/repo/blame.go

@@ -15,13 +15,13 @@ import (
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/charset"
 	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/git/languagestats"
 	"code.gitea.io/gitea/modules/highlight"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/templates"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/services/context"
-	files_service "code.gitea.io/gitea/services/repository/files"
 )
 
 type blameRow struct {
@@ -234,7 +234,7 @@ func processBlameParts(ctx *context.Context, blameParts []*git.BlamePart) map[st
 func renderBlame(ctx *context.Context, blameParts []*git.BlamePart, commitNames map[string]*user_model.UserCommit) {
 	repoLink := ctx.Repo.RepoLink
 
-	language, err := files_service.TryGetContentLanguage(ctx.Repo.GitRepo, ctx.Repo.CommitID, ctx.Repo.TreePath)
+	language, err := languagestats.GetFileLanguage(ctx, ctx.Repo.GitRepo, ctx.Repo.CommitID, ctx.Repo.TreePath)
 	if err != nil {
 		log.Error("Unable to get file language for %-v:%s. Error: %v", ctx.Repo.Repository, ctx.Repo.TreePath, err)
 	}