Install package support

[RossComputerGuy]

core.make("osjs/package").install(url) should be a function, it should install the application/package and restart the server and refresh the page.

[andersevenrud]

Yep. Mr @aherreraGH has requested this as well, and it's been a long standing item on my todo list.

You don't actually have to restart the server if a package is installed as the manifest is updated in the client automatically via a signal.

However, the server will need to accept a signal that tells it to load all new package server files.

This should also be configurable as an external service in case the distro requires the installed files to require some spesific permission or user/group combination.

[andersevenrud]

Superseeded by #106