Add file tree to file view page (#32721)

Resolve #29328

This pull request introduces a file tree on the left side when reviewing
files of a repository.

---------

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

modules/git/parse_nogogit.go

@@ -19,7 +19,7 @@ func ParseTreeEntries(data []byte) ([]*TreeEntry, error) {
 	return parseTreeEntries(data, nil)
 }
 
-// parseTreeEntries FIXME this function's design is not right, it should make the caller read all data into memory
+// parseTreeEntries FIXME this function's design is not right, it should not make the caller read all data into memory
 func parseTreeEntries(data []byte, ptree *Tree) ([]*TreeEntry, error) {
 	entries := make([]*TreeEntry, 0, bytes.Count(data, []byte{'\n'})+1)
 	for pos := 0; pos < len(data); {

modules/git/tree_blob_gogit.go

@@ -21,6 +21,7 @@ func (t *Tree) GetTreeEntryByPath(relpath string) (*TreeEntry, error) {
 		return &TreeEntry{
 			ID: t.ID,
 			// Type: ObjectTree,
+			ptree: t,
 			gogitTreeEntry: &object.TreeEntry{
 				Name: "",
 				Mode: filemode.Dir,