Prompt user to download sites about zeronet

[HelloZeroNet]

I think it could work this way:

• By default every site has 10MB size limit
• If the site used 80% of its limit zeronet displays a notification when you visit the site: This site want to store more data than current limit: 10MB. [Incrase limit to 20MB]
• The limit steps: 10MB, 20MB, 50MB, 100MB, 500MB, 1GB, 5GB, 10GB, Unlimited
• If a new update to content.json comes in and the total size of site exceed the limit then the update will be rejected.
• If you visit a new site and its size larger than 10MB then the notification will be displayed on the loading screen and the download wont be started until you give the permission

[shakna-israel]

As a side not, prompting for downloading may need to include other warnings.

E.g. A user should be able to cancel the download of a site that contains materials illegal in their country.

Something like a NSFW warning before downloading. It would have to rely on site creators, but it's a nice workaround.

[HelloZeroNet]

Added in version 0.2.1:

NSFW warning can be added later if necessary