Zite download incomplete when size > 20mb

When adding a zite that has more than 20MB, zeronet will ask only once if you want to increase the site size from 10MB to 20MB and it will leave the download incomplete with no indication of that fact.

**To reproduce:**
1. Open Antilibrary.bit -> It will ask you to increase the size from 10 to 20mb, accept that
2. Once the download seems to be done check the folder `ZeroBundle\ZeroNet\data\147nKEb9bBJgBDgQytEQhmiGjF8e6HkEua\data\json`, you should have 32 folders in there (al_1 - al_32) but you will have only 7
3. There are no indications that the site download is incomplete so the user won't notice it.

**Expected behaviour:**
1. ZeroNet should ask me if I want to increase the site size to +10mb from the total size calculated from the files in content.json.
2. Is should also give some indication of the download status (not the download progress bar) **while in the site page**. Something that will highlight to the user that he is missing files and the site download is not complete.

Start with the Antilibrary.bit reproduction and inspect content.json alongside the downloaded data folders. Trace why the site size is increased only once and how download state is exposed while viewing the site. Done means larger sites request the needed size and clearly indicate incomplete downloads in the site page.

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