Make package installer a sequence of alert-dialogs.

To make sure the dialog does not change height a single content for all
steps of the sequence. We just unhide the view that should actually be
shown.

Also added a night-mode theme.

Test: Manually uninstalled, installed and update package.
      atest CtsNoPermissionTestCases
            CtsNoPermissionTestCases25
	    CtsPackageInstallTestCases
	    CtsPackageUninstallTestCases
	    CtsPackageInstallerTapjackingTestCases
Change-Id: I890bb1f2697df3af87b6cb65e460f611334523ee