0Net does not delete deleted optional files from site directory

### Step 1: Please describe your environment

* ZeroNet version: 0.7.1 (Rev:4399)
* Operating system: Windows 10
* Web browser: Firefox 72.0.2
* Tor status: always
* Opened port: no

### Step 2: Describe the problem:

In ZeroUp,KopyKate, and files menu i deleted some files.In the site directory still exit the picemap.msg and the deleted files too. This takes up space unnecessarily. The program does not want to delete them.Too much trash file collect this way the program.

#### Steps to reproduce:

1. Upload a file to ZeroUp,KopyKate, etc.
2. Delete file from the site and files menu too.

#### Observed Results:

In the site directory/user folder the picemap.msg and files does not deleted!

#### Expected Results:

Too much trash file collect this way the program.Which cannot be separated from the seeded files if the user seed for many files.

Start with the deletion flow exposed by ZeroUp, KopyKate, and the files menu, then trace how the site directory/user folder is cleaned after a file is removed. Reproduce the upload-then-delete steps and verify that deleted optional files and picemap.msg no longer remain while seeded files are preserved.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.