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>

custom/conf/app.example.ini

@@ -197,13 +197,6 @@ RUN_USER = ; git
 ;; relative paths are made absolute relative to the APP_DATA_PATH
 ;SSH_SERVER_HOST_KEYS=ssh/gitea.rsa, ssh/gogs.rsa
 ;;
-;; Directory to create temporary files in when testing public keys using ssh-keygen,
-;; default is the system temporary directory.
-;SSH_KEY_TEST_PATH =
-;;
-;; Use `ssh-keygen` to parse public SSH keys. The value is passed to the shell. By default, Gitea does the parsing itself.
-;SSH_KEYGEN_PATH =
-;;
 ;; Enable SSH Authorized Key Backup when rewriting all keys, default is false
 ;SSH_AUTHORIZED_KEYS_BACKUP = false
 ;;
@@ -294,6 +287,9 @@ RUN_USER = ; git
 ;; Default path for App data
 ;APP_DATA_PATH = data ; relative paths will be made absolute with _`AppWorkPath`_
 ;;
+;; Base path for App's temp files, leave empty to use the managed tmp directory in APP_DATA_PATH
+;APP_TEMP_PATH =
+;;
 ;; Enable gzip compression for runtime-generated content, static resources excluded
 ;ENABLE_GZIP = false
 ;;
@@ -1069,15 +1065,6 @@ LEVEL = Info
 ;; Separate extensions with a comma. To line wrap files without an extension, just put a comma
 ;LINE_WRAP_EXTENSIONS = .txt,.md,.markdown,.mdown,.mkd,.livemd,
 
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;[repository.local]
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;;
-;; Path for local repository copy. Defaults to `tmp/local-repo` (content gets deleted on gitea restart)
-;LOCAL_COPY_PATH = tmp/local-repo
-
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;[repository.upload]
@@ -1087,9 +1074,6 @@ LEVEL = Info
 ;; Whether repository file uploads are enabled. Defaults to `true`
 ;ENABLED = true
 ;;
-;; Path for uploads. Defaults to `data/tmp/uploads` (content gets deleted on gitea restart)
-;TEMP_PATH = data/tmp/uploads
-;;
 ;; Comma-separated list of allowed file extensions (`.zip`), mime types (`text/plain`) or wildcard type (`image/*`, `audio/*`, `video/*`). Empty value or `*/*` allows all types.
 ;ALLOWED_TYPES =
 ;;
@@ -2594,9 +2578,6 @@ LEVEL = Info
 ;; Currently, only `minio` and `azureblob` is supported.
 ;SERVE_DIRECT = false
 ;;
-;; Path for chunked uploads. Defaults to APP_DATA_PATH + `tmp/package-upload`
-;CHUNKED_UPLOAD_PATH = tmp/package-upload
-;;
 ;; Maximum count of package versions a single owner can have (`-1` means no limits)
 ;LIMIT_TOTAL_OWNER_COUNT = -1
 ;; Maximum size of packages a single owner can use (`-1` means no limits, format `1000`, `1 MB`, `1 GiB`)