Fix unintented depenedency issue

Fix unintented depenedency issue

Only one user-agent per target should be installed.
If per target agent has dependency on the main package,
conflict packages should be declared to avoid multiple target agent installation.

Thus, this patch defines the conflict packages for each user-agent per target.

Eventually, per-target agent will be removed.There are per-ux specifc agent will be created.
For example, circle-ux-agent, box-ux-agent, no-ux-agent.

Change-Id: I2b20879adb7e67997e3805b6193a2301c561b17d