Support for nested bundles in setApplicationRestrictions

Added new restriction types - bundle and bundle-array.

Modified RestrictionsManager.getManifestRestrictions to support new
hierarchical restrictions.
Added RestrictionsManager.convertRestrictionsToBundle, which enables
programmatic conversion from a list of RestrictionEntries to a Bundle.

Modified read/write methods for application restrictions in UserManagerService.
Added unit tests.

Bug: 19540606
Change-Id: I32b264e04d5d177ea5b4c39a8ace5ee0ce907970