[M108 Migration][VD][UWE] Change Chromium TPK to WAS App

[M108 Migration][VD][UWE] Change Chromium TPK to WAS App

This patch includes:

1. Change Chromium TPK type from BIU to WAS by removing 2 metadatas.
The BIU(BuiltInUpgrade) app is installed unconditionally,
and the WAS type app can set the installation conditions.

When considering flash size,
Chromium TPK should not be installed unconditionally.

2. Add new metadata, "postinstall.launch"
WAS executes mount daemon when an app containing "postinstall.launch"
metadata is installed or updated.

Reference:
  - https://review.tizen.org/gerrit/#/c/272769/

Change-Id: I9e04337f6ad976a265091d7d2088db0d0ca53bd5
Signed-off-by: jiangyuwei <yuwei.jiang@samsung.com>