Move some functions to gitrepo package (#35543)

Refactor Git command functions to use WithXXX methods instead of
exposing RunOpts.
This change simplifies reuse across gitrepo and improves consistency,
encapsulation, and maintainability of command options.

---------

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

modules/repository/create_test.go

@@ -8,6 +8,7 @@ import (
 
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unittest"
+	"code.gitea.io/gitea/modules/gitrepo"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -16,7 +17,7 @@ func TestGetDirectorySize(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	repo, err := repo_model.GetRepositoryByID(t.Context(), 1)
 	assert.NoError(t, err)
-	size, err := getDirectorySize(repo.RepoPath())
+	size, err := gitrepo.CalcRepositorySize(repo)
 	assert.NoError(t, err)
 	repo.Size = 8165 // real size on the disk
 	assert.Equal(t, repo.Size, size)