This mod fixes the following upload cache problems:

(1)
If one uploads many files (dropping files test0.bin-test9.bin in one move) races may occur and file id in DOM won't match file ids in web upload dir on server, i.e.:

```
$(".AttachmentListContainer tbody tr").filter(function() { console.log("%s, %d", $(this).find('td.Filename').text(), $(this).find('a').data('file-id'))})
test9.bin, 10
test8.bin, 8
test7.bin, 8
test6.bin, 7
test5.bin, 4
test4.bin, 5
test3.bin, 3
test2.bin, 3
test1.bin, 2
test0.bin, 1
```

This may be fixed with patch (which unblocks updating all file ids on upload not just for one file)...

```
--- a/var/httpd/htdocs/js/Core.UI.js   2021-11-08 18:53:34.088284466 +0100
+++ b/var/httpd/htdocs/js/Core.UI.js 2021-12-16 18:41:14.090199778 +0100
@@ -697,10 +697,6 @@

                                 $TargetObj = $ExistingItemObj.closest('tr');

-                                if ($TargetObj.find('a').data('file-id')) {
-                                    return;
-                                }
-
                                 $TargetObj
                                     .find('.Filetype')
                                     .text(Attachment.ContentType)
```

...but using file ids for identification of uploaded files is not race condition resistant; to provoke race condition apply patch

```
--- a/Kernel/Modules/AjaxAttachment.pm 2021-06-19 21:59:34.379471088 +0200
+++ b/Kernel/Modules/AjaxAttachment.pm       2021-12-16 18:38:28.943925139 +0100
@@ -56,6 +56,10 @@
             Param => 'Files',
         );

+        if ($UploadStuff{Filename} eq 'test01.bin') {
+            sleep(1);
+        }
+
         $UploadCacheObject->FormIDAddFile(
             FormID      => $Self->{FormID},
             Disposition => 'attachment',
@@ -67,6 +71,10 @@
             FormID => $Self->{FormID},
         );

+        if ($UploadStuff{Filename} eq 'test02.bin') {
+            sleep(2);
+        }
+
         my @AttachmentData;
```

and drop files test01.bin and test02.bin (same size) in one move; after upload there will be:

```
$(".AttachmentListContainer tbody tr").filter(function() { console.log("%s, %d", $(this).find('td.Filename').text(), $(this).find('a').data('file-id'))})
test02.bin, 1
test01.bin, 1
```

not

```
test02.bin, 2
test01.bin, 1
```

This problem was solved by removing unnecessarry FileID attribute from upload data struct to avoid any races that may occurr between filename list and fileid list. Only filename will be used to identify items added to upload cache.

(2)
Double clicking trash icon to remove attachment generates two requests to server and one will cause an error.

(3)
Web form is not removed from upload cache dir after saving or updating template.

(4)
Unused upload handling code removed.

Author-Change-Id: IB#1113065

Added missing part of 6e42dbb.

Fixes: 6e42dbb
Author-Change-Id: IB#1113065

Code policy cleanups.

Fixes: 6e42dbb
Author-Change-Id: IB#1113065

Fixes: 6e42dbb
Author-Change-Id: IB#1113065

Will be moved to separate issue.

Fixes: 53a7ba6
Author-Change-Id: IB#1113065

Fixes: 6e42dbb
Author-Change-Id: IB#1113065

Parameter name regression fixed.

Fixes: 2d608b05303537e10c75a453f941026e58c2b9eb
Author-Change-Id: IB#1113065

Author-Change-Id: IB#1113065