Disk quota usage meter and management option in admin panel

[DanWin]

To prevent disk usage abuse by a single user, a quota should be enforced, which should be extendable on request

[DanWin]

A quota has now been introduced. A graphical usage meter and an option in the admin panel to extend the quota are still to be done.

[011248163264]

it will be nice, also an option for other diskquotas 10Gb 20Gb 30GB, so users can select this as an option.

[MuzahidGithub]

Graphical disk uses widget is introduced in my design. But it just ui not functional yet.

[DanWin]

Upgradable quotas and dashboard usage meter were introduced in 0e0fb54 using CoinPayments API
Now there is only a management page in the admin panel left.