Create symbolic link to /usr/bin/WebProcess for app with dynamic box

Create symbolic link to /usr/bin/WebProcess for app with dynamic box

- Tizen application is registered to app_info DB on installation time, hence
  this change needs to be done in wrt-installer

[Issue]    N/A
[Problem]  wrt-plugins (or external root daemon) cannot retrieve appid properly
           based on the pid of Box WebProcess.
[Cause]    app_manager API which gets appid from pid considers only
           registered executable path on app_info DB.
           (app_manager gets executable path from /proc/<pid>/cmdline
             matched to pid of WebProcess)
[Solution] WebProcess associated with the box needs to be registered to
           app_info DB on installation time.
           1. Register symbolic link (/usr/bin/WebProcess) per box
           2. Register the box's new appid to app_info DB on installation time

Change-Id: Ic6b59de89d6428b83f705da51c791806ac94e3ce