AppsOnSd feature - Add default container

Add new remote interface to do temporary copies. The new
remote stub handling is done on mHandler thread and doesn't need locking
for now.
Add new InstallArgs class and subclasses to isolate cases for installation.
Move resource deletion for failed installs/upgrades to later on in installation
cycle.
Fix code path for forward locked apps when using scanPackageLI

TODO's
Fix installation paths to completely use InstallArgs based design later on.
Get rid of using flags in various install/uninstall code paths.
Ideally InstallArgs should be created using these flags and used in the
rest of the code.
Function renames.
Revisit mount api's.