Optional large file sharing/downloading major difficulties and problems

### Step 1: Please describe your environment

* ZeroNet version: 0.7.1 (rev4486) and all previous versions
* Operating system: Windows 10
* Web browser: Firefox 76.0.1
* Tor status: always
* Opened port: no

### Step 2: Describe the problem:

1. Auto download big file size limit 10MB preset value: Many files are larger than 10MB.A less knowledgeable user don't know what this feature is for. If the page contains 20MB 100MB 1GB file the user can not download it. The other problem is that the user does not know what size have the largest file on the page.From files under 10MB non optional files such as HTML can even total 1GB/site.And for files larger than 10MB optional files can even altogether 40MB in the same site.

2. If in the content.json file not set the optional files then files what larger than 10MB they cannot be downloaded: A beginner website owner will not be able to set it.Users cannot download the files larger than 10MB.There are no easy-to-find detailed descriptions on how to set this up.

3. When the page loads,large files which are larger than 10MB cannot be downloaded automatically.These files doe not seeded correcly in single sites this way.And in many cases, users cannot download it.Very confusing because they are part of the website in the same way. It can greatly degrade the enjoyment value of pages.

4. Can not resume files download without seed button: If nobody seed the file it cannot be set up easily to try to download the files the program later.

5. Priority: It takes a lot of time for the pages to appear: HTML,CSS,Pictures,js should download first to load the pages faster.When the download of these files is complete.The other files will be loaded even later.Which are not displayed by the browser.

#### Steps to reproduce:

Create a simple simple user website below and above 10MB mixed files.If the site contains 1GB under 10MB non optional files.And total 500GB mixed files 15-100MB files the problems are spectacular.But with a simple index.html and a 20MB file setup also given the problems.