Application origin definition should take into account packaged applications

[mounirlamouri]

For the moment, it takes only into account the hosted applications and then later in the text, the origin of a packaged application is defined.

CC: @marcoscaceres @ming-jin

[marcoscaceres]

From when I read the spec, I found the two origin types to be fairly clear. I think this will become more clear as we continue to work on this, so I would be fine with closing this for now.