Don't allow to users add images to the any series

[php-coder]

We should limit adding images to series only to users with special permissions or to owners of this series.

After feedback from: Pavel Finkelshtein (aka @asm0dey)

[php-coder]

Could be implemented after #108 where we adding limit for quantity of images per user. Also we should allow to admin add any number of images to any series.