Uniform all temporary directories and allow customizing temp path (#32352)

This PR uniform all temporary directory usage so that it will be easier
to manage.

Relate to #31792 

- [x] Added a new setting to allow users to configure the global
temporary directory.
- [x] Move all temporary files and directories to be placed under
os.Temp()/gitea.
- [x] `setting.Repository.Local.LocalCopyPath` now will be
`setting.TempPath/local-repo` and the customized path is removed.
```diff
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;[repository.local]
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;; Path for local repository copy. Defaults to  TEMP_PATH + `local-repo`, this is deprecated and cannot be changed
-;LOCAL_COPY_PATH = local-repo
```

- [x] `setting.Repository.Upload.TempPath` now will be
`settting.TempPath/uploads` and the customized path is removed.
```diff
;[repository.upload]
-;;
-;; Path for uploads. Defaults to TEMP_PATH + `uploads`
-;TEMP_PATH = uploads
```

- [x] `setting.Packages.ChunkedUploadPath` now will be
`settting.TempPath/package-upload` and the customized path is removed.
```diff
;[packages]
-;;
-;; Path for chunked uploads. Defaults it's `package-upload` under `TEMP_PATH` unless it's an absolute path.
-;CHUNKED_UPLOAD_PATH = package-upload
```

- [x] `setting.SSH.KeyTestPath` now will be
`settting.TempPath/ssh_key_test` and the customized path is removed.
```diff
[server]
-;;
-;; Directory to create temporary files in when testing public keys using ssh-keygen,
-;; default is the system temporary directory.
-;SSH_KEY_TEST_PATH =
```

TODO:
- [ ] setting.PprofDataPath haven't been changed because it may need to
be kept until somebody read it but temp path may be clean up any time.

---------

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

modules/setting/path.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/tempdir"
 )
 
 var (
@@ -196,3 +197,18 @@ func InitWorkPathAndCfgProvider(getEnvFn func(name string) string, args ArgWorkP
 	CustomPath = tmpCustomPath.Value
 	CustomConf = tmpCustomConf.Value
 }
+
+// AppDataTempDir returns a managed temporary directory for the application data.
+// Using empty sub will get the managed base temp directory, and it's safe to delete it.
+// Gitea only creates subdirectories under it, but not the APP_TEMP_PATH directory itself.
+// * When APP_TEMP_PATH="/tmp": the managed temp directory is "/tmp/gitea-tmp"
+// * When APP_TEMP_PATH is not set: the managed temp directory is "/{APP_DATA_PATH}/tmp"
+func AppDataTempDir(sub string) *tempdir.TempDir {
+	if appTempPathInternal != "" {
+		return tempdir.New(appTempPathInternal, "gitea-tmp/"+sub)
+	}
+	if AppDataPath == "" {
+		panic("setting.AppDataPath is not set")
+	}
+	return tempdir.New(AppDataPath, "tmp/"+sub)
+}