[Addon Setting App] Uninstallation from device

[Addon Setting App] Uninstallation from device

 When user selects 'X' button for unistallation,
 it not only removes the addon from addon DB file
 but also unistalls the addon package from device.

 - Handle pkgid(package id) field for each installed addon
 - The pkgid is passed to wrtjs when user selects to uninstall
 - WRTjs eventually invokes package manager API to uninstall
   the addon package as you can see in [1] and [2]
 - To use the package manager API, this app needs to have
   privilege http://tizen.org/privilege/packagemanager.install
   and also be packed to wgt with platform privilege level

 [1] https://review.tizen.org/gerrit/213786
 [2] https://review.tizen.org/gerrit/213787

Change-Id: I547ea9a3aea8487a5759c1886435911819b7491c
Signed-off-by: hyunduk.kim <hyunduk.kim@samsung.com>