Add preload web app for installer

Add preload web app for installer

[Issue#] N/A
[Problem] N/A
[Cause] N/A
[Solution]
1. Add command "-ip" for preload webapp.
2. skip verify certificate during install preload webapp.
3. Add show install error during generate binary.
4. Preload web app cann't uninstall.
5. preload widget source file will be removed if installation success after install webapp.
[SCMRequest] This package should release with wrt-commons.

Change-Id: Ibd6d82f49d0c7d9026edd64d508afb75170a7095