Limit feature of optional file of one zite in sidebar.

**Is your feature request related to a problem? Please describe.**

When I help to distribute the optional file of Millchan in one vps with 10 GB free space and I donot know how many optional files would be downloaded into my VPS (the default vaule for big file is 1MB), hours later, I found more than 8 GB optional files of Millchan were downloade into my VPS and they were increasing, I have to delete this zite because this zite would use up all of my free space. I just wanted to help download some new optional file of this zite and the total size of optional flie of this zite should be limited into 1 GB. However, when I click the help to distribute button, more than 8 GB optional files were downloaded into my vps.

**Describe the solution you'd like**
I wish there is a choice in the sidebar that would limit the maximum size of optional files of that zite.