In freedesktop.org specification, the category is Network. Most applications
under this category can also be used in local network, like FTP client,
browsers, P2P clients, cloud storage clients. So I think "Network" is the
best name for this category.
The "Internet>Terminal" category actually doesn't include anything because it
doesn't have a `<Include>` block. "Terminal" sub-category is already included
in "System" category. So I removed it.