modularization to cut down storage usage

There are many apps in aid learning, but for some users, they just need one or two of them. I think all the apps are based on a basic linux environment. So why not just install the essential components at first and give a graphic panel or one-line-commands for users to install the apps they need. In this way we can cut down both downloading time in the first boot and the storage usage and we can also upgrade apps independently.