Calibre it not limited to storing ebook files, it can store just about any file type. At least one person stores NC embroidery pattern files. But writing plugins to do the installs or fetching app store data might be a stretch. Most plugins are written by people who need them.
Have you looked at any of the x-platform app development frameworks, providing an app deployment facility seems more like their bailiwick.
BR
Moderator Notice
I moved your thread. Read the sticky at the top of the Development sub-forum. You don't appear to be proposing to do the development work yourself